All questions of June Week 4 for Class 10 Exam

A

¶¶¶ we have Sn = n^2 + 7n
and to find out the 3rd term we must have first term i.e, (a) and a common difference i.e, ( d)

so let's use the above situation ¶¶¶
put n = 1
S1 = (1)^2 + 7×1
S1 = 8
we know that S1 = a1 = 8 ( first term)

now put n = 2 ¶¶¶
S2 = (2)^2 + 7×2
S2 = 18
we also know that
a2 = S2 - S1
a2 = 18 - 8
a2 = 10

now for common difference :- ¶¶¶
d= a2- a1
d = 10 - 8
d= 2

now we have a = 8 and d = 2 so let's find out the 3rd term i.e, a3= a+2d
= 8 +2 × 2
= 8 + 4
a3 = 12
so the third term is 12... .. ¶¶¶¶¶

In organic chemistry, an alkane, or paraffin (a historical name that also has other meanings), is an acyclic saturated hydrocarbon. In other words, an alkane consists of hydrogen and carbon atoms arranged in a tree structure in which all the carbon–carbon bonds are single. Alkanes have the general chemical formula CnH2n+2. The alkanes range in complexity from the simplest case of methane (CH4), where n = 1 (sometimes called the parent molecule), to arbitrarily large and complex molecules, like pentacontane (C50H102) or 6-ethyl-2-methyl-5-(1-methylethyl)octane, an isomer of tetradecane (C14H30)

Fuel is not burning completely because there is a lack of oxygen. Hence, incombustion is taking place over here.

Pottassium permanganate is a very strong oxidant able to react with many functional groups, such as secondary alcohols, 1,2-diols , aldehydes, alkenes, oxides, sulphides and thiols. Under controlled conditions potassium permanganate oxidizes primary alcohols into alcoholic acids very efficiently. I think you understand this.

Correct answer is option D because in this case Hydrogen is being added in the compound given and no elimination or substitution is done.

Products obtained after the combustion of methane:
Methane is a hydrocarbon compound consisting of one carbon atom bonded to four hydrogen atoms (CH4). When methane undergoes combustion, it reacts with oxygen (O2) to produce various products.

1. Heat:
Combustion reactions are highly exothermic, meaning they release a large amount of heat energy. This is due to the breaking and forming of chemical bonds during the reaction. The combustion of methane results in the production of heat energy, which can be utilized for various applications.

2. Water:
One of the products obtained from the combustion of methane is water (H2O). The hydrogen atoms present in methane combine with the oxygen from the air to form water molecules. This is an important aspect of the combustion process as it contributes to the overall energy release.

3. Carbon Dioxide:
Another product formed during the combustion of methane is carbon dioxide (CO2). The carbon atom in methane combines with two oxygen atoms from the air to produce carbon dioxide. This is a greenhouse gas that contributes to climate change when released into the atmosphere.

4. Light:
During the combustion process, the release of heat energy is often accompanied by the emission of light. This light emission is typically seen as a flame when methane is burned in an open environment. The color and intensity of the flame can vary depending on the conditions of combustion.

Summary:
In summary, the products obtained after the combustion of methane are heat, water, carbon dioxide, and light. The combustion reaction involves the breaking of methane bonds and the formation of new bonds with oxygen. This process releases heat energy, produces water molecules, generates carbon dioxide, and emits light. These products have various applications and implications, making methane combustion an important process to understand in fields such as energy production and environmental science.

Addition of hydrogen across C-C double bonds is called hydrogenation. Unsaturated hydrocarbons add hydrogen in the presence of catalysts such as nickel/palladium to give saturated hydrocarbons. Vegetable oils used for cooking are long unsaturated hydrocarbons which are healthy.

Answer:

The correct answer is option 'A'.

Explanation:

Classification of Symbols

In the given symbol, there are four characters, i.e., $, ., :, and -. Each character has its own significance in the symbol. Let's classify these characters:

• $ - It is a symbol of currency, and its value is commonly known as a dollar.

• . - It is a decimal point that separates the whole number from the fractional part.

• : - It is a symbol of time, and it is used to separate hours from minutes.

• - - It is a hyphen, which is used to join two words or separate two parts of a word.

Interpretation of the Symbol

Using the above classification, we can interpret the given symbol as follows:

$ . : - It is a combination of currency, decimal point, time, and a hyphen. Therefore, it can be interpreted as follows:

• It represents an amount of money.

• The amount has a decimal value.

• The amount is related to time.

• The amount is connected with something else using a hyphen.

Options Explanation

a) This option is the correct answer because it represents the interpretation of the symbol as we have explained above.

b) This option is incorrect because it does not represent the interpretation of the symbol. The symbol does not represent a mathematical operation.

c) This option is incorrect because it does not represent the interpretation of the symbol. The symbol does not represent a unit of measurement.

d) This option is incorrect because it does not represent the interpretation of the symbol. The symbol does not represent a musical note.

Conclusion

In conclusion, the given symbol represents an amount of money with a decimal value that is related to time and connected with something else using a hyphen. The correct option is 'A'.