Class 10 Science: CBSE (Official) Marking Scheme with Solution (2025-2026) | Science Class 10 PDF Download

 Page 1


SCIENCE – Code no. 086  
MARKING SCHEME  
CLASS – X (2025-26) 
Section – A 
1 
C. Cuscuta, ticks, lice, leeches and tapeworm; as all of these are parasites. 
1 
2 
B.  Lactic acid + Energy 
1 
3 
D. Blood pressure: Medulla in hindbrain 
1 
4 
D. insulin from pancreas 
1 
5 
A. BB x bb 
1 
6 
B. (ii), (iii), (iv)   
1 
7 
C. Use of plastic as packaging material.  
1 
8 
A. Both A and R are true, and R is the correct explanation of A.  
1 
9 
D. A is false but R is true 
1 
10 It is completely wrong to say that plants do not produce any excretory 
products.                                                                                                       
However, plants use completely different strategies for excretion than those 
of the animals. They get rid of these wastes in different manner (any two):  
i. Oxygen, a photosynthetic waste, is removed through stomata. 
ii. Excess water is removed by transpiration through stomata. 
iii. Other metabolic wastes are either stored in dead cells, resins and 
gums or are removed through falling of old leaves.  
iv. Many waste products are stored in cellular vacuoles                       
2 
11 Students to attempt either option A or B. 
A.   
(i)  There are two chambers in the heart of fish. The blood is pumped to 
the gills, is oxygenated there and passes directly to the rest of the 
body. 
(ii) There are four chambers in the heart of a human being. Separation 
of the right side and the left side of the heart by septum prevents 
mixing of oxygenated and de-oxygenated bloods  
OR 
B. Xylem moves water and minerals obtained from the soil through roots to 
all other parts of the plant in a unidirectional manner// Transpiration 
takes place from leaf which causes a transpirational pull in the tracheids 
and vessels of xylem facilitating upward movement of water// roots 
2 
Page 2


SCIENCE – Code no. 086  
MARKING SCHEME  
CLASS – X (2025-26) 
Section – A 
1 
C. Cuscuta, ticks, lice, leeches and tapeworm; as all of these are parasites. 
1 
2 
B.  Lactic acid + Energy 
1 
3 
D. Blood pressure: Medulla in hindbrain 
1 
4 
D. insulin from pancreas 
1 
5 
A. BB x bb 
1 
6 
B. (ii), (iii), (iv)   
1 
7 
C. Use of plastic as packaging material.  
1 
8 
A. Both A and R are true, and R is the correct explanation of A.  
1 
9 
D. A is false but R is true 
1 
10 It is completely wrong to say that plants do not produce any excretory 
products.                                                                                                       
However, plants use completely different strategies for excretion than those 
of the animals. They get rid of these wastes in different manner (any two):  
i. Oxygen, a photosynthetic waste, is removed through stomata. 
ii. Excess water is removed by transpiration through stomata. 
iii. Other metabolic wastes are either stored in dead cells, resins and 
gums or are removed through falling of old leaves.  
iv. Many waste products are stored in cellular vacuoles                       
2 
11 Students to attempt either option A or B. 
A.   
(i)  There are two chambers in the heart of fish. The blood is pumped to 
the gills, is oxygenated there and passes directly to the rest of the 
body. 
(ii) There are four chambers in the heart of a human being. Separation 
of the right side and the left side of the heart by septum prevents 
mixing of oxygenated and de-oxygenated bloods  
OR 
B. Xylem moves water and minerals obtained from the soil through roots to 
all other parts of the plant in a unidirectional manner// Transpiration 
takes place from leaf which causes a transpirational pull in the tracheids 
and vessels of xylem facilitating upward movement of water// roots 
2 
actively uptake ions from the soil, leading to difference in concentration 
gradient, thereby water moves into the roots to eliminate this difference/ 
creating a steady movement of water into root xylem.                                                      
12 Tree food chain- tree, zebra, tiger /Any other food chain  
Grassland food chain- grass, zebra, tiger / Any other food chain 
Food web- Join the two food chains at a common point (zebra)  
2 
13 ? All information from our environment is detected by the specialised tips 
of some nerve cells. The information acquired at the end of the dendritic 
tip of a nerve cell (Fig. a), sets off a chemical reaction that creates an 
electrical impulse. 
? This impulse travels from the dendrite to the cell body, and then along 
the axon to its end. At the end of the axon, the electrical impulse sets off 
the release of some chemicals. 
? These chemicals cross the gap, or synapse, and start a similar electrical 
impulse in a dendrite of the next neuron. This is how nervous impulses 
travel in the body. (Fig b). 
 
3 
14 A. RY, Ry, rY, ry                                                                                          
B. The traits which are independently inherited are as follows                   
Tall round: 81  
Tall wrinkled: 27  
Short round: 27  
Short wrinkled: 9  
(Ratio :- 9 : 3 : 3 : 1) 
3 
15 Students to attempt either subpart A or B.  
A. Eggs are rich in proteins. The digestion of proteins is initiated in the 
stomach. Gastric glands present in the wall of the stomach release 
4 
Page 3


SCIENCE – Code no. 086  
MARKING SCHEME  
CLASS – X (2025-26) 
Section – A 
1 
C. Cuscuta, ticks, lice, leeches and tapeworm; as all of these are parasites. 
1 
2 
B.  Lactic acid + Energy 
1 
3 
D. Blood pressure: Medulla in hindbrain 
1 
4 
D. insulin from pancreas 
1 
5 
A. BB x bb 
1 
6 
B. (ii), (iii), (iv)   
1 
7 
C. Use of plastic as packaging material.  
1 
8 
A. Both A and R are true, and R is the correct explanation of A.  
1 
9 
D. A is false but R is true 
1 
10 It is completely wrong to say that plants do not produce any excretory 
products.                                                                                                       
However, plants use completely different strategies for excretion than those 
of the animals. They get rid of these wastes in different manner (any two):  
i. Oxygen, a photosynthetic waste, is removed through stomata. 
ii. Excess water is removed by transpiration through stomata. 
iii. Other metabolic wastes are either stored in dead cells, resins and 
gums or are removed through falling of old leaves.  
iv. Many waste products are stored in cellular vacuoles                       
2 
11 Students to attempt either option A or B. 
A.   
(i)  There are two chambers in the heart of fish. The blood is pumped to 
the gills, is oxygenated there and passes directly to the rest of the 
body. 
(ii) There are four chambers in the heart of a human being. Separation 
of the right side and the left side of the heart by septum prevents 
mixing of oxygenated and de-oxygenated bloods  
OR 
B. Xylem moves water and minerals obtained from the soil through roots to 
all other parts of the plant in a unidirectional manner// Transpiration 
takes place from leaf which causes a transpirational pull in the tracheids 
and vessels of xylem facilitating upward movement of water// roots 
2 
actively uptake ions from the soil, leading to difference in concentration 
gradient, thereby water moves into the roots to eliminate this difference/ 
creating a steady movement of water into root xylem.                                                      
12 Tree food chain- tree, zebra, tiger /Any other food chain  
Grassland food chain- grass, zebra, tiger / Any other food chain 
Food web- Join the two food chains at a common point (zebra)  
2 
13 ? All information from our environment is detected by the specialised tips 
of some nerve cells. The information acquired at the end of the dendritic 
tip of a nerve cell (Fig. a), sets off a chemical reaction that creates an 
electrical impulse. 
? This impulse travels from the dendrite to the cell body, and then along 
the axon to its end. At the end of the axon, the electrical impulse sets off 
the release of some chemicals. 
? These chemicals cross the gap, or synapse, and start a similar electrical 
impulse in a dendrite of the next neuron. This is how nervous impulses 
travel in the body. (Fig b). 
 
3 
14 A. RY, Ry, rY, ry                                                                                          
B. The traits which are independently inherited are as follows                   
Tall round: 81  
Tall wrinkled: 27  
Short round: 27  
Short wrinkled: 9  
(Ratio :- 9 : 3 : 3 : 1) 
3 
15 Students to attempt either subpart A or B.  
A. Eggs are rich in proteins. The digestion of proteins is initiated in the 
stomach. Gastric glands present in the wall of the stomach release 
4 
hydrochloric acid, a protein digesting enzyme called pepsin and mucus. 
The hydrochloric acid creates an acidic medium which facilitates the 
action of enzyme pepsin.                                                                        
     OR 
B. Eggs contain fats. Bile juice from the liver breaks down large fat globules 
into smaller ones for increasing the efficiency of the enzymes and making 
the medium alkaline. Emulsified fats are digested by lipase secreted by 
pancreas.                                                                                                
C. Sweet potatoes are rich in starch. The saliva secreted by salivary glands 
present in buccal cavity contain an enzyme called salivary amylase that 
breaks down starch which is a complex molecule to give sugar.              
D. Small Intestine will have a maximum amount of digested food as the 
process of digestion is completed in the small intestine.                        
For Visually impaired students 
D. The digested food is taken up by the inner lining of the intestine with the 
help of finger-like projections or villi which increase the surface area for 
the absorption.                                                                                        
16 Student to attempt either option A or B. 
(i) Puneet should not choose seeds as banana plants have lost the 
capacity to produce seeds. He should go for vegetative propagation 
of banana (by stem cutting).                                                                    
(ii) Errors and variations in DNA copying cause variation.             
Variation is good as it can help a population tide over unfavourable 
conditions by survival of some variants.                                         
It is bad as parents’ desirable characters are lost/ sometimes variants 
are not able to survive in the new conditions/ the variant is not able to 
use the cellular apparatus efficiently.                                                 
OR 
(i) Watermelon has unisexual flowers, the male and female flowers are 
separate.  
The presence of pollinators will facilitate cross pollination between the 
flowers increasing the chance of fertilization and number of fruits 
being produced. Without pollinators the probability of pollen falling on 
stigma reduces in a unisexual flower, especially if they are far apart 
thus the number of fruits produced will be less.                               
(ii) The three changes observed are: 
? Ovule develops a tough coat and becomes seed.                     
? Ovary grows and ripens to form fruit.                                         
? Petals, sepals, stamen, style and stigma may shrivel and fall off. 
5 
Section – B  
17 D.  Both equations 1 and 2 are redox reactions, p= 2 and q=10   1 
18 
B. (I) and (III) 
1 
Page 4


SCIENCE – Code no. 086  
MARKING SCHEME  
CLASS – X (2025-26) 
Section – A 
1 
C. Cuscuta, ticks, lice, leeches and tapeworm; as all of these are parasites. 
1 
2 
B.  Lactic acid + Energy 
1 
3 
D. Blood pressure: Medulla in hindbrain 
1 
4 
D. insulin from pancreas 
1 
5 
A. BB x bb 
1 
6 
B. (ii), (iii), (iv)   
1 
7 
C. Use of plastic as packaging material.  
1 
8 
A. Both A and R are true, and R is the correct explanation of A.  
1 
9 
D. A is false but R is true 
1 
10 It is completely wrong to say that plants do not produce any excretory 
products.                                                                                                       
However, plants use completely different strategies for excretion than those 
of the animals. They get rid of these wastes in different manner (any two):  
i. Oxygen, a photosynthetic waste, is removed through stomata. 
ii. Excess water is removed by transpiration through stomata. 
iii. Other metabolic wastes are either stored in dead cells, resins and 
gums or are removed through falling of old leaves.  
iv. Many waste products are stored in cellular vacuoles                       
2 
11 Students to attempt either option A or B. 
A.   
(i)  There are two chambers in the heart of fish. The blood is pumped to 
the gills, is oxygenated there and passes directly to the rest of the 
body. 
(ii) There are four chambers in the heart of a human being. Separation 
of the right side and the left side of the heart by septum prevents 
mixing of oxygenated and de-oxygenated bloods  
OR 
B. Xylem moves water and minerals obtained from the soil through roots to 
all other parts of the plant in a unidirectional manner// Transpiration 
takes place from leaf which causes a transpirational pull in the tracheids 
and vessels of xylem facilitating upward movement of water// roots 
2 
actively uptake ions from the soil, leading to difference in concentration 
gradient, thereby water moves into the roots to eliminate this difference/ 
creating a steady movement of water into root xylem.                                                      
12 Tree food chain- tree, zebra, tiger /Any other food chain  
Grassland food chain- grass, zebra, tiger / Any other food chain 
Food web- Join the two food chains at a common point (zebra)  
2 
13 ? All information from our environment is detected by the specialised tips 
of some nerve cells. The information acquired at the end of the dendritic 
tip of a nerve cell (Fig. a), sets off a chemical reaction that creates an 
electrical impulse. 
? This impulse travels from the dendrite to the cell body, and then along 
the axon to its end. At the end of the axon, the electrical impulse sets off 
the release of some chemicals. 
? These chemicals cross the gap, or synapse, and start a similar electrical 
impulse in a dendrite of the next neuron. This is how nervous impulses 
travel in the body. (Fig b). 
 
3 
14 A. RY, Ry, rY, ry                                                                                          
B. The traits which are independently inherited are as follows                   
Tall round: 81  
Tall wrinkled: 27  
Short round: 27  
Short wrinkled: 9  
(Ratio :- 9 : 3 : 3 : 1) 
3 
15 Students to attempt either subpart A or B.  
A. Eggs are rich in proteins. The digestion of proteins is initiated in the 
stomach. Gastric glands present in the wall of the stomach release 
4 
hydrochloric acid, a protein digesting enzyme called pepsin and mucus. 
The hydrochloric acid creates an acidic medium which facilitates the 
action of enzyme pepsin.                                                                        
     OR 
B. Eggs contain fats. Bile juice from the liver breaks down large fat globules 
into smaller ones for increasing the efficiency of the enzymes and making 
the medium alkaline. Emulsified fats are digested by lipase secreted by 
pancreas.                                                                                                
C. Sweet potatoes are rich in starch. The saliva secreted by salivary glands 
present in buccal cavity contain an enzyme called salivary amylase that 
breaks down starch which is a complex molecule to give sugar.              
D. Small Intestine will have a maximum amount of digested food as the 
process of digestion is completed in the small intestine.                        
For Visually impaired students 
D. The digested food is taken up by the inner lining of the intestine with the 
help of finger-like projections or villi which increase the surface area for 
the absorption.                                                                                        
16 Student to attempt either option A or B. 
(i) Puneet should not choose seeds as banana plants have lost the 
capacity to produce seeds. He should go for vegetative propagation 
of banana (by stem cutting).                                                                    
(ii) Errors and variations in DNA copying cause variation.             
Variation is good as it can help a population tide over unfavourable 
conditions by survival of some variants.                                         
It is bad as parents’ desirable characters are lost/ sometimes variants 
are not able to survive in the new conditions/ the variant is not able to 
use the cellular apparatus efficiently.                                                 
OR 
(i) Watermelon has unisexual flowers, the male and female flowers are 
separate.  
The presence of pollinators will facilitate cross pollination between the 
flowers increasing the chance of fertilization and number of fruits 
being produced. Without pollinators the probability of pollen falling on 
stigma reduces in a unisexual flower, especially if they are far apart 
thus the number of fruits produced will be less.                               
(ii) The three changes observed are: 
? Ovule develops a tough coat and becomes seed.                     
? Ovary grows and ripens to form fruit.                                         
? Petals, sepals, stamen, style and stigma may shrivel and fall off. 
5 
Section – B  
17 D.  Both equations 1 and 2 are redox reactions, p= 2 and q=10   1 
18 
B. (I) and (III) 
1 
19 B. Iron nail is coated with a brown coating in test tube ‘P’ and silver coating 
in test tube ‘Q’. 
1 
20 
B. Red Yellow 
 
1 
21 D. Sodium hydroxide 1 
22 B. insoluble calcium carbonate converts to water soluble calcium 
bicarbonate.  
1 
23 D. NaCl 1 
24 D. A is false but R is true 1 
25 A. The pin will drop but will take less time to drop because silver is a better 
conductor of heat than aluminium. 
B. No, aluminium wire will not melt because metals have high melting points. 
2 
26 Attempt either option A or B.   
A.  
(i) No, ‘X’ is highly reactive and will catch fire.                                   
(ii) Sodium.  
It is extracted from molten sodium chloride by electrolytic      
reduction                                                                                        
Cathode:  Na
+
 + e
-
 ? Na 
Anode:  2Cl
-
 ? Cl2 + 2e
-
 
       (Potassium is also a correct option)                                               
OR 
B.  
(i) Copper gets oxidised/corroded to basic copper carbonate which is 
greenish in colour.                                                                         
(ii) No, iron will rust and the reddish layer of rust will come off exposing 
iron to air, the dome will not be stable. Copper on the other hand on 
corrosion forms a protective layer which does not allow further 
corrosion.                                                                                        
(iii) Copper is a highly malleable metal, its thin sheets can be used to 
give different shapes of roofs, like the shape of a dome.               
3 
27 
A. She was expecting Oxygen gas to be formed at the anode and hydrogen 
at the cathode.                                                                                       
B. Distilled water is a poor conductor of electricity.                                   
C. Adding few drops of H2SO4 or some NaCl (or any other strong 
electrolyte).                                                                                           
For visually impaired students 
A. Redox reaction                                                                                      
3 
 
 
 
Page 5


SCIENCE – Code no. 086  
MARKING SCHEME  
CLASS – X (2025-26) 
Section – A 
1 
C. Cuscuta, ticks, lice, leeches and tapeworm; as all of these are parasites. 
1 
2 
B.  Lactic acid + Energy 
1 
3 
D. Blood pressure: Medulla in hindbrain 
1 
4 
D. insulin from pancreas 
1 
5 
A. BB x bb 
1 
6 
B. (ii), (iii), (iv)   
1 
7 
C. Use of plastic as packaging material.  
1 
8 
A. Both A and R are true, and R is the correct explanation of A.  
1 
9 
D. A is false but R is true 
1 
10 It is completely wrong to say that plants do not produce any excretory 
products.                                                                                                       
However, plants use completely different strategies for excretion than those 
of the animals. They get rid of these wastes in different manner (any two):  
i. Oxygen, a photosynthetic waste, is removed through stomata. 
ii. Excess water is removed by transpiration through stomata. 
iii. Other metabolic wastes are either stored in dead cells, resins and 
gums or are removed through falling of old leaves.  
iv. Many waste products are stored in cellular vacuoles                       
2 
11 Students to attempt either option A or B. 
A.   
(i)  There are two chambers in the heart of fish. The blood is pumped to 
the gills, is oxygenated there and passes directly to the rest of the 
body. 
(ii) There are four chambers in the heart of a human being. Separation 
of the right side and the left side of the heart by septum prevents 
mixing of oxygenated and de-oxygenated bloods  
OR 
B. Xylem moves water and minerals obtained from the soil through roots to 
all other parts of the plant in a unidirectional manner// Transpiration 
takes place from leaf which causes a transpirational pull in the tracheids 
and vessels of xylem facilitating upward movement of water// roots 
2 
actively uptake ions from the soil, leading to difference in concentration 
gradient, thereby water moves into the roots to eliminate this difference/ 
creating a steady movement of water into root xylem.                                                      
12 Tree food chain- tree, zebra, tiger /Any other food chain  
Grassland food chain- grass, zebra, tiger / Any other food chain 
Food web- Join the two food chains at a common point (zebra)  
2 
13 ? All information from our environment is detected by the specialised tips 
of some nerve cells. The information acquired at the end of the dendritic 
tip of a nerve cell (Fig. a), sets off a chemical reaction that creates an 
electrical impulse. 
? This impulse travels from the dendrite to the cell body, and then along 
the axon to its end. At the end of the axon, the electrical impulse sets off 
the release of some chemicals. 
? These chemicals cross the gap, or synapse, and start a similar electrical 
impulse in a dendrite of the next neuron. This is how nervous impulses 
travel in the body. (Fig b). 
 
3 
14 A. RY, Ry, rY, ry                                                                                          
B. The traits which are independently inherited are as follows                   
Tall round: 81  
Tall wrinkled: 27  
Short round: 27  
Short wrinkled: 9  
(Ratio :- 9 : 3 : 3 : 1) 
3 
15 Students to attempt either subpart A or B.  
A. Eggs are rich in proteins. The digestion of proteins is initiated in the 
stomach. Gastric glands present in the wall of the stomach release 
4 
hydrochloric acid, a protein digesting enzyme called pepsin and mucus. 
The hydrochloric acid creates an acidic medium which facilitates the 
action of enzyme pepsin.                                                                        
     OR 
B. Eggs contain fats. Bile juice from the liver breaks down large fat globules 
into smaller ones for increasing the efficiency of the enzymes and making 
the medium alkaline. Emulsified fats are digested by lipase secreted by 
pancreas.                                                                                                
C. Sweet potatoes are rich in starch. The saliva secreted by salivary glands 
present in buccal cavity contain an enzyme called salivary amylase that 
breaks down starch which is a complex molecule to give sugar.              
D. Small Intestine will have a maximum amount of digested food as the 
process of digestion is completed in the small intestine.                        
For Visually impaired students 
D. The digested food is taken up by the inner lining of the intestine with the 
help of finger-like projections or villi which increase the surface area for 
the absorption.                                                                                        
16 Student to attempt either option A or B. 
(i) Puneet should not choose seeds as banana plants have lost the 
capacity to produce seeds. He should go for vegetative propagation 
of banana (by stem cutting).                                                                    
(ii) Errors and variations in DNA copying cause variation.             
Variation is good as it can help a population tide over unfavourable 
conditions by survival of some variants.                                         
It is bad as parents’ desirable characters are lost/ sometimes variants 
are not able to survive in the new conditions/ the variant is not able to 
use the cellular apparatus efficiently.                                                 
OR 
(i) Watermelon has unisexual flowers, the male and female flowers are 
separate.  
The presence of pollinators will facilitate cross pollination between the 
flowers increasing the chance of fertilization and number of fruits 
being produced. Without pollinators the probability of pollen falling on 
stigma reduces in a unisexual flower, especially if they are far apart 
thus the number of fruits produced will be less.                               
(ii) The three changes observed are: 
? Ovule develops a tough coat and becomes seed.                     
? Ovary grows and ripens to form fruit.                                         
? Petals, sepals, stamen, style and stigma may shrivel and fall off. 
5 
Section – B  
17 D.  Both equations 1 and 2 are redox reactions, p= 2 and q=10   1 
18 
B. (I) and (III) 
1 
19 B. Iron nail is coated with a brown coating in test tube ‘P’ and silver coating 
in test tube ‘Q’. 
1 
20 
B. Red Yellow 
 
1 
21 D. Sodium hydroxide 1 
22 B. insoluble calcium carbonate converts to water soluble calcium 
bicarbonate.  
1 
23 D. NaCl 1 
24 D. A is false but R is true 1 
25 A. The pin will drop but will take less time to drop because silver is a better 
conductor of heat than aluminium. 
B. No, aluminium wire will not melt because metals have high melting points. 
2 
26 Attempt either option A or B.   
A.  
(i) No, ‘X’ is highly reactive and will catch fire.                                   
(ii) Sodium.  
It is extracted from molten sodium chloride by electrolytic      
reduction                                                                                        
Cathode:  Na
+
 + e
-
 ? Na 
Anode:  2Cl
-
 ? Cl2 + 2e
-
 
       (Potassium is also a correct option)                                               
OR 
B.  
(i) Copper gets oxidised/corroded to basic copper carbonate which is 
greenish in colour.                                                                         
(ii) No, iron will rust and the reddish layer of rust will come off exposing 
iron to air, the dome will not be stable. Copper on the other hand on 
corrosion forms a protective layer which does not allow further 
corrosion.                                                                                        
(iii) Copper is a highly malleable metal, its thin sheets can be used to 
give different shapes of roofs, like the shape of a dome.               
3 
27 
A. She was expecting Oxygen gas to be formed at the anode and hydrogen 
at the cathode.                                                                                       
B. Distilled water is a poor conductor of electricity.                                   
C. Adding few drops of H2SO4 or some NaCl (or any other strong 
electrolyte).                                                                                           
For visually impaired students 
A. Redox reaction                                                                                      
3 
 
 
 
B. Decomposition reaction and endothermic reaction                                  
C. Combination reaction and exothermic reaction                                       
28 A. (b) < 40, because concentrated H2SO4 gives more H+ ions than dilute 
acid. 
B. 3 mL of H2SO4 will be 60 drops, which will neutralise 6 mL of NaOH 
S. No. Volume of dil 
NaOH taken (mL) 
Drops of dil 
H2SO4 used 
1 2 20 (1 mL) 
2 3 30 (1.5 mL) 
3 4 40 (2 mL) 
4 6 3 mL = 60 drops 
 
OR 
Colour will change from colourless to pink. Phenolphthalein in 
colourless in acids and turns pink in basic solution. 
  
C. 2NaOH + H2SO4 ? Na2SO4 + 2H2O 
(a) neutralisation and double displacement reaction. 
Base NaOH is getting neutralised and forming salt + water. It is 
double displacement as Na
+
 ions are being replaced by H
+
 and OH
-
 
by SO4
2-
. It is not precipitation reaction because Na2SO4 is soluble in 
water. 
4 
29 Student to attempt either option A or B. 
A.  
(a) x = 3, y = 6 
(b) Propene 
(c)   
 
 
 
 
 
(d) Propanol 
(e) C3H6 + H2   
Ni
     C3H8 
CH2=CH-CH3 + H2     CH3-CH2-CH3 
OR 
B.  
(a) Ionic bond 
(b) Q2P 
(c) Basic, metallic oxides are basic in nature.  
(d) 2C2H5OH +2Q ? 2C2H5OQ + H2 
(e) CP2  
 
For visually impaired students 
A.  
(a) x = 3, y = 6 
5