Test: Acids, Bases & Salts- Assertion & Reason Type Questions- 1


15 Questions MCQ Test Science Class 10 | Test: Acids, Bases & Salts- Assertion & Reason Type Questions- 1


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Attempt Test: Acids, Bases & Salts- Assertion & Reason Type Questions- 1 | 15 questions in 30 minutes | Mock test for Class 10 preparation | Free important questions MCQ to study Science Class 10 for Class 10 Exam | Download free PDF with solutions
QUESTION: 1

Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:

Assertion: After white washing the walls, a shiny white finish on walls is obtained after two to three days.

Reason: Calcium Oxide reacts with Carbon dioxide to form Calcium Hydrogen Carbonate which gives shiny white finish.

Solution: Calcium hydroxide is obtained by reaction of calcium oxide and water.
QUESTION: 2

Assertion (A): When zinc is added to dilute hydrochloric acid, hydrogen is given off.

Reason (R): Hydrochloric acid molecules contain chloride and hydroxide ions.

Solution:

The metal zinc readily reacts with hydrochloric acid to produce hydrogen gas (H2) and zinc chloride (ZnCl2).

QUESTION: 3

Assertion (A): Gas bubbles are observed when sodium carbonate is added to dilute hydrochloric acid.

Reason (R): Carbon dioxide is given off in the reaction.

Solution: Sodium carbonate reacts with excess hydrochloric acid to form sodium chloride, water and carbon dioxide. In this reaction, bubbles of carbon dioxide are observed.
QUESTION: 4

Assertion (A): Ammonia solution is an alkali.

Reason (R): Ammonia solution turns blue litmus paper red.

Solution: Ammonia solution, which is alkaline, turns the red litmus paper blue.
QUESTION: 5

Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:

Assertion (A): When common salt is kept open, it absorbs moisture from the air.

Reason (R): Common salt contains magnesium chloride.

Solution:
QUESTION: 6

Assertion (A): Baking soda creates acidity in the stomach.

Reason (R): Baking soda is alkaline.

Solution: Baking soda, being alkaline, neutralises the acidity in the stomach and removes it.
QUESTION: 7

Assertion (A): Plaster of Paris is used by doctors for setting fractured bones.

Reason (R): When Plaster of Paris is mixed with water and applied around the fractured limbs, it sets into a hard mass.

Solution: Plaster of Paris when mixed with water and applied around the fractured limbs, it sets into a hard mass and keeps the bone joints in a fixed position. So, it is commonly used for setting fractured bones.
QUESTION: 8

Direction: In the Following Questions, A Statement of Assertion (A) Is Followed by A Statement of Reason (R). Mark The Correct Choice As:

Assertion: While dissolving an acid or base in water, the acids must always be added slowly to water with constant stirring.

Reason: Dissolving an acid on a base in water is a highly exothermic reaction.

Solution:

Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).

QUESTION: 9

Assertion : On adding H2SO4 to water the resulting aqueous solution gets corrosive.

Reason: Hydronium ions are responsible for corrosive action.

Solution:

Because H2SO4 is a strong acid, it readily forms hydronium ions when dissolved in water which are responsible for its corrosive action.

QUESTION: 10

Assertion : Phenolphthalein gives pink colour in basic solution.

Reason : Phenolphthalein is a natural indicator.

Solution:

Phenolphthalein is often used as an indicator in acid-base titrations. It will appear pink in basic solutions and clear in acidic solutions. Hence, phenolphthalein is chosen because it changes colour in a pH range between 8.3 – 10. But it is not a natural indicator.

QUESTION: 11

Assertion: HCl gas does not change the colour of dry blue litmus paper.

Reason: HCl gas dissolves in the water present in wet litmus paper to from H+ ions.

Solution:

Both assertion (A) and reason (R) are true, R is not the correct explanation of assertion (A).

QUESTION: 12

Assertion : HCl produces hydronium ions (H3O+) and chloride ions (Cl-) in aqueous solution.

Reason : In presence of water, basic give H+ ions.

Solution: Assertion (A) is true but reason (R) is false. HCl produces H+ ions in aqueous solution because in the presence of water, acids give H+ ions. As H+ ions cannot exist alone so it combines with water molecules and forms H3O+.
QUESTION: 13

Assertion: Sodium hydroxide reacts with zinc to produce hydrogen gas.

Reason : Acids react with active metals to produce hydrogen gas.

Solution: Sodium hydroxide being a strong base, reacts with active metal (zinc) to produce H2 gas. The reaction is given as follows

Zn (s) + 2NaOH (aq) → Na2ZmO2 (aq)+ H2 (g)

QUESTION: 14

Assertion : Ammonia solution is an alkali.

Reason : Ammonia solution turns blue litmus paper red.

Solution:

Ammonia gas, which is alkaline, turn the red litmus paper blue.

QUESTION: 15

Assertion : To dilute concentrated sulphuric acid water is added to the acid slowly.

Reason : A lot of heat energy will be given out in the dilution of concentrated sulphuric acid.

Solution:

Water is never added to concentrated sulphuric acid as it is an exothermic reaction and releases a large amount of heat energy. It also results in spurting of the acid, which can burn your skin. Concentrated sulphuric acid is added to water in small amounts and that too with constant stirring and cooling.

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