Practice Chemistry ncert - general science mcq Online Quiz (set-1) For All Competitive Exams

Q-1)   A solution turns red litmus blue. The pH of solution is

(a)

(b)

(c)

(d)


Q-2)   Two elements gallium and oxygen combine to form a compound Ga2O3. Which among the following is the valency of gallium ?

(a)

(b)

(c)

(d)


Q-3)   The concentration of hydrochloric acid in a given solution is 10–8 M. What is the value of pH for this solution ?

(a)

(b)

(c)

(d)


Q-4)   Which of the following is a weak base ?

(a)

(b)

(c)

(d)

Explanation:

NH4OH as it is not get completely ionized in aqueous solution.


Q-5)   If pH of A, B, C and D are 9.5, 2.5, 3.5 and 5.5 respectively, then strongest acid is

(a)

(b)

(c)

(d)

Explanation:

Less the pH, more acidic is the solution.

The pH of acid B is 2.5 which is minimum.


Q-6)   Natural indicator litmus is extracted from

(a)

(b)

(c)

(d)

Explanation:

Natural indicator is obtained from lichens and is purple in colour. It turns acidic solution red and basic solution blue.


Q-7)   When eno salt is poured into the water, bubbles forms, which is due to

(a)

(b)

(c)

(d)


Q-8)   Baking powder is

(a)

(b)

(c)

(d)


Q-9)   Reaction of an acid with a base is known as –

(a)

(b)

(c)

(d)

Explanation:

In a neutralization reaction an acid reacts with a base and forms salt and water.


Q-10)   Which of the following is considered a mineral acid ?

(a)

(b)

(c)

(d)


Q-11)   Sodawater obtained by passing carbon dioxide in water is

(a)

(b)

(c)

(d)


Q-12)   Which among the following statements with regard to pH scale is/are correct?
  1. It is a logarithmic scale.
  2. The scale is limited to 0-14 because the ionic product of water is about $10^{-14}$
  3. The lower the value of pH, the greater the acidity of the solution.
Select the correct answer using the code given below

(a)

(b)

(c)

(d)

Explanation:


Q-13)   An unknown gas quickly dissolves in water. This gaseous aqueous solution turns red litmus into the blue. This gas produces hydrogen chloride with a white flame. This unknown gas is

(a)

(b)

(c)

(d)


Q-14)   What is Neela thotha?

(a)

(b)

(c)

(d)


Q-15)   Human stomach produces acid ‘X’ which helps in digestion of food. Acid ‘X’ is

(a)

(b)

(c)

(d)


Q-16)   Why bases are kept in glass bottles?

(a)

(b)

(c)

(d)


Q-17)   Universal indicator solution is named as such because

(a)

(b)

(c)

(d)

Explanation:

It can be for entire pH range.


Q-18)   Which of the following pairs of substances are chemically same?

(a)

(b)

(c)

(d)


Q-19)   Plaster of Paris hardens by –

(a)

(b)

(c)

(d)

Explanation:

$CaSO_4.{1/2}H_2O+3/2H_2O ⟶ {CaSO_4}.2H_2O$


Q-20)   The chemical formula of washing soda is

(a)

(b)

(c)

(d)

Explanation: