Practice Questions set 2 - general science mcq Online Quiz (set-1) For All Competitive Exams

Q-1)   Approximately, how many different chemical elements exist in the Earth?

(a) 300

(b) 200

(c) 250

(d) 100

Q-2)   Which of the following is a fundamental element?

(a) Sand

(b) Marble

(c) Diamond

(d) Sugar

Q-3)   The chemical composition of diamond is

(a) Carbon

(b) Nickel

(c) Nitrogen

(d) Zinc

Q-4)   Consider the following statements with reference to the periodic table of chemical elements.

1. Ionization potential gradually decreases along a period.
2. In a group of elements, electron affinity decreases as the atomic weight increases.
3. In a given period, electronegativity decreases as the atomic number increases.

Which of these statement(s) is/are correct?

(a) Only 1

(b) 1 and 3

(c) Only 2

(d) 2 and 3

Q-5)   The element found maximum in the soil layer is

(a) Oxygen

(b) Manganese

(c) Nitrogen

(d) Silicon

Q-6)   Which is the most abundant element after oxygen?

(a) Silicon

(b) Sodium

(c) Carbon

(d) Chlorine

Q-7)   When iron is left exposed in open air, it gets rusted. Which constituent(s) of air is /are responsible for rusting iron?

1. Oxygen gas present in air
2. Moisture present in air
3. Carbon dioxide gas present in air

Select the correct answer using the code given below :

(a) 1 and 2

(b) 2 only

(c) 1 only

(d) 2 and 3

Q-8)   Consider the following statements :

1. Solid NaCl conducts electricity.
2. Bauxite is purified by chemical separation.
3. Copper is purified by electrolytic refining.

Which of these statements are correct ?

(a) 2 and 3

(b) 1 and 3

(c) 1 and 2

(d) 1, 2 and 3

Q-9)   Match List-I with List-II :

List-I (Compound)	List-II (Use)
A. Cellulose nitrate	1. Soft soap
B. Potassium sulphate	2. Gun powder
C. Potassium salt of fatty acids	3. Fertilizer
D. Calcium oxide	4. Glass

Select the correct answer from the codes given below: (A) (B) (C) (D)

(a) 4 1 2 3

(b) 3 2 1 4

(c) 2 3 1 4

(d) 3 1 2 4

Q-10)   Which of the following statements about pH and $H^+$ ion concentration are incorrect?

1. The addition of one drop of concentrated HCl in NH₄OH solution decreases the pH of the solution.
2. A solution of the mixture of one equivalent of each of CH₃COOH and NaOH has a pH of 7.
3. The pH of pure neutral water is not zero.
4. A cold and concentrated H₂SO₄ has a lower $H^+$ ion concentration than a dilute solution of $H_2SO_4$.

(a) 1, 2 and 4

(b) 1, 3 and 4

(c) 1, 2 and 3

(d) 2, 3 and 4