Acids, Bases & Salts- important MCQ , assertion-reason and case study based questions

MULTIPLE CHOICE QUESTIONS

   1.  The colour of phenolphthalein in acidic medium is -

(a)   Yellow

(b)   Pink

(c)   Colourless

(d)   Blue

   2.  Generally, when certain metals react with an acid, they release gas.

(a)   Nitrogen

(b)   Oxygen

(c)   Hydrogen

d) Argon

3.  Milkiness of lime water disappear when excess CO2 is passed due to the formation of -

(a)   Calcium hydroxide

(b)   Calcium chloride

(c)   Calcium bicarbonate

(d)   Calcium carbonate

   4.  What is formed when zinc reacts with sodium hydroxide?

(a)   Zinc hydroxide and sodium

(b)   Sodium zincate and hydrogen gas

(c)   Sodium zinc-oxide and hydrogen gas

(d)   Sodium zincate and water

   5.  The common name for the substance used as antacid -

(a)   Washing soda

(b)   Plaster of Paris

(c)   Bleaching powder

(d)   Baking soda

   6.  Rain is called acid rain when it's:

(a)   pH falls below 7

(b)   pH falls below 6

(c)   pH falls below 5.6

(d)   pH is above 7

7.  When you clean a metal vessel with tamarind the reaction taking place is:

Metaloxide + X--------- Salt + Water. What is X here?

(a)   Acid

(b)   Base

(c)   Hydrogen

(d)   Carbon dioxide

    8.  Sodium hydroxide turns phenolphthalein solution

(a)   pink

(b)   yellow

(c)   colourless

(d)   orange

9.  Sodium carbonate is a basic salt because it is a salt of a

(a)   strong acid and strong base

(b)   weak acid and weak base

(c)   strong acid and weak base

(d)   weak acid and strong base

10. Which one of the given is true, if a substance has a pH value of 7?

(a)   The substance is a base

(b)   The substance is an acid

(c)   The substance is a neutral substance

(d)   Either (A) or (B)

ASSERTION AND REASON QUESTIONS

DIRECTION: Each of these questions contains an Assertion followed by Reason. Read them carefully and answer the question on the basis of following options. You have to select the one that best describes the two statements.

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

(b)   Both A and R are true and R is not the correct explanation of A.

(c)   A is true but R is false.

(d)   A is false but R is true.

1.  Assertion (A): The acid must be added to water with constant stirring.

Reason (R): Mixing of an acid with water decreases the concentration of H+ ions per unit volume.

2.  Assertion (A): On heating, colour of hydrated copper sulphate changes from blue to white.

Reason (R): On strong heating, Copper sulphate crystals lose all the water of crystallisation and form anhydrous salt.

3.  Assertion (A): The aqueous solution of glucose and alcohol do not show acidic character.

Reason (R ): Aqueous solution of glucose and alcohol do not give H+ ions .

4.  Assertion (A): HCl gas does not change the colour of dry blue litmus paper.

Reason (R): HCl gas dissolves in the water present in wet litmus paper to form H+ ions

5.  Assertion (A): Weak acids have low electrical conductivity.

Reason (R ): Strong acids and weak acids have equal concentration of H+ ions in their solutions.

CASE STUDY BASED QUESTIONS

1.  A copper vessel gets tarnished due to formation of an oxide layer on its surface. On rubbing lemon on the vessel, the surface is cleaned, and the vessel begins to shine again. This is due to the fact that it reacts with the acid present in lemon to form a salt which is washed away with water. As a result, the layer of copper oxide is removed from the surface of the vessel and the shining surface is exposed.

i).  Which of the following acids is present in lemon?

(a)   Formic acid

(b)   Acetic acid

(c)   Citric acid

(d)   Hydrochloric acid

ii).  The nature of copper oxide is

(a)   acidic

(b)   basic

(c)   neutral

(d)   amphoteric

iii).  Name the salt formed in the above reaction

(a)   copper carbonate

(b)   copper chloride

(c)   copper citrate

(d)   copper citrate

iv).  The phenomenon of copper getting tarnished is

(a)   corrosion

(b)   rancidity

(c)   displacement

(d)   none of these

1.  Taj Mahal, the seventh wonder of the world, is made of white stone. This white stone contains the same substance ‘A’ that is present in chalk powder and lime-stone. It is turning yellow due to polluted air. If it is cleaned by an acidic cleaner, a gas ‘B’ is released, which when passed through a solution ‘C’, forms the same substance which is present in the white stone that was used to make Taj mahal.

 

 

 

 

1.1.  The substance A is -

(A)  Ca3CO2

(B)  CaCO3

(C)   Ca(OH)2

(D)  CaSO4

1.2.  Gas B is -

(A)  Hydrogen

(B)  Nitrogen

(C)   Chlorine

(D)  Carbon dioxide

1.3.  Solution C is -

(A)  CaCl2

(B)  CaCO3

(C)   Ca(OH)2

(D)  CaSO4

1.1.   What is the nature of the substance A?

(A)  Acidic

(B)  Basic

(C)   Neutral

(D)  None

1.2.   The polluted air around Taj mahal leads to the following problem because of which it is getting Marble cancer:

(A)  Global Warming

(B)  Acid Rain

(C)   Green House Effect

(D)  All are correct

2.  Salt of a strong acid and strong base is neutral with a pH value of 7. NaCl common salt is formed by a combination of hydrochloric acid and sodium

hydroxide solution. This is the salt that is used in food. Some salt is called rock salt which was formed when seas of bygone ages dried up. The common salt thus obtained is an important raw material for various materials of daily use, such as sodium hydroxide, baking soda, washing soda, and bleaching powder.

1.  Which of the following does not form an acidic salt?

(a)   Phosphoric acid

(b)   Carbonic acid (c)Hydrochloric acid

(d) Sulphuric acid

2.  Which of the following salts has no water of crystallization?

(a)   Copper sulphate

(b)   Washing soda

(c) Baking soda

(d)   Gypsum

1.  The formula of baking soda is -

(a)   NaCl

(b)   KHCO3

(c)   NaHCO3

(d)   Na2CO3

2.  Which of the following is treated with chlorine to obtain bleaching powder

(a)   Ca SO4

(b)   Ca (OH)2

(c)   Mg (OH)2

(d)   KOH