CBSE Class 10 Chemistry Acids Bases And Salts Worksheet Set 05

Assertion and Reason Type MCQs :

Following questions consists of two statements – Assertion (A) and Reason (R). Answer these questions selecting the appropriate option given below:
A. Both assertion and reason are true, and reason is the correct explanation of assertion.
B. Both assertion and reason are true, but reason is not the correct explanation of assertion.
C. Assertion is true but reason is false.
D. Assertion is false and reason is true.\

Question. Assertion (A): The HCl gas shows acidic behaviour in the water.
Reason(R): The pH of dry HCl gas is 1.5.

Answer: C

Question. Assertion: NaOH reacts with zinc metal and produces hydrogen gas.
Reason: Acids react with active metals to produce hydrogen gas.

Answer: B

Question. Assertion(A): Washing soda is a chemical compound that can be used to remove stubborn stains from laundry
Reason(R):The sodium carbonate in washing soda "softens" water.

Answer: B

Question. Assertion (A): Phenolphthalein is a synthetic acid-base indicator.
Reason(R): Phenolphthalein does not give any colour with acids but gives pink colour with bases.

Answer: A

Question. Assertion(A): Baking powder is used in making cake instead of using only baking soda.
Reason(R) : Baking powder contains Tartaric acid which reacts with sodium carbonate and removes bitter taste.

Answer: C

Question. Assertion (A): Honey bee-sting injects an acid in the skin which causes pain and irritation.
Reason (R): Use of mild base like baking soda on the stung area gives relief.

Answer: B

Question. Assertion (A): The organic compounds such as C₆H₁₂O₆ and C₂H₅OH contain hydrogen but they do not conduct electricity in the water.
Reason(R): Acids produce H₃O+ ions in the solutions.

Answer: B

Question. Assertion(A): Soda-acid fire extinguisher contains sodium hydrogen carbonate and sulphuric acid.
Reason(R): Sulphuric acid mixes with sodium hydrogen carbonate solution and produces a lot of CO₂ gas, which forms a blanket over fire and cuts it off from the supply of the air to the burning substance and the fire stops.

Answer: A

Question. Assertion (A): The acid must always be added to water with constant stirring.
Reason(R): Mixing of an acid with water decreases the conc. of H+ ions per unit volume.

Answer: B

CASE BASED MCQs

I. Bleaching powder is a pale yellowish powder. It is soluble in water but due to the presence of impurities, we never observe a clear solution. Its chemical formula is Ca(OCl₂) with its chemical name as Calcium hypochlorite. Bleaching powder is also called calcium chlorohypochlorite because it is considered as a mixed salt of hydrochloric acid and hypochlorous acid.

Question. One of the following cannot be considered as the use of bleaching powder
A. It is an oxidising agent.
B. it is used for disinfecting water.
C. it bleaches cotton and linen in the textile industry.
D.. it releases Oxygen gas on heating which can be used for aeration of water bodies.

Answer: D

Question. The compound lime water that is used in the manufacture of bleaching powder is
A.Clear solution of Ca(OH)₂.
B.Milky Suspension of Ca(OH)₂.
C.Clear solution of CaCl₂.
D.Clear solution of CaCO₃.

Answer: A

Question. One of the products obtained during the electrolysis of aqueous Sodium Chloride(brine) used in the preparation of Bleaching powder is.
A. Sodium metal at cathode
B.Hydrogen gas
C. Chlorine gas
D. Slaked lime.

Answer: C

II. Water of crystallisation is the fixed number of water molecules present in one formula unit of a salt. water(s) of crystallization or water(s) of hydration are water molecules that are present inside crystals. Water is often incorporated in the formation of crystals from aqueous solutions. A salt with associated water of crystallization is known as a hydrate.

Question. The temperature at which Gypsum (CaSO₄ . 2H₂O) into Plaster of Paris(CaSO₄.1/2 H₂O
A.373 K
B.273 K
C.374 K
D.375 K

Answer: A

Question. The formula of Plaster of Paris is CaSO4. ½ H2O, it is to be noted that half water molecule is shown to be attached as water of crystallisation. This indicates that
A. Only half water molecule is present in Calcium Sulphate crystal
B. Two formula units of Calcium Sulphate share one molecule of water.
C. Two formula units of calcium Sulphate share two molecules of water
D. Two formula units of Calcium Sulphate share one and a half molecules of water.

Answer: B

Question. Which of the following salt does not contain water of crystallisation?
A. Blue Vitriol
B.Baking Soda
C.Washing Soda
D.Gypsum.

Answer: B

Fill in the Blanks :

Question: Anhydrous sodium carbonate is commonly known as ............... .
Answer: Soda ash

Question: When an acid reacts with a metal carbonate or metal hydrogen carbonate, it gives the corresponding salt, .......... gas and ............... .
Answer: Carbon dioxide, water

Question: .......................... is the fixed number of water molecules chemically attached to each formula unit of a salt in its crystalline form.
Answer: Water of crystallisation

Question: ENO contains .......... and is ........... in nature.
Answer: Sodium hydrogen carbonate, basic

Question: Soda–acid fire extinguisher contains a solution of sodium hydrogen carbonate and ............... .
Answer: Sulphuric acid

True / False :

Question: Washing soda on strong heating gives sodium oxide and carbon dioxide.
Answer: False

Question: Mixing concentrated acids or bases with water is a highly endothermic process. 
Answer: False

Question: Bleaching powder is used for disinfecting drinking water.
Answer: True

Question: Acids and bases neutralise each other to form corresponding salts and water. 
Answer: True

Question: Plaster of paris is obtained by heating gypsum at 373 K in a kiln.
Answer: True