Chemistry (CDS-Solved Paper)

Total Questions: 50

1. Bose-Einstein condensate is a [Evening Shift-2019 (II)]

Correct Answer: (b) fifth state of matter
Solution:

Bose-Einstein Condensate (BEC) is a fifth state of matter. The BEC is formed by working a gas of extremely low density, about one- hundred tons and the density of normal air to super low temperatures. Other states of matter : Solid, liquid, gas and plasma.

2. The rate of evaporation of liquid does not depend upon [Evening Shift-2019 (II)]

Correct Answer: (c) its mass
Solution:

The rate of evaporation of liquid does not depend upon its mass, because it is a surface phenomenon. Factors affecting evaporation are:
● An increase in surface area
● An increase in temperature
● Humidity

3. Rutherford’s alpha particle scattering experiment on thin gold foil was responsible for the discovery of [Evening Shift-2019 (II)]

Correct Answer: (c) atomic nucleus
Solution:

Rutherford’s alpha particle scattering experiment leads to the discovery of atomic nucleus. He proposed that, there is a positively charged spherical centre in an atom, called nucleus.

4. Consider the following statements : [Evening Shift-2019 (II)]

1. Particles of matter intermix on their own.
2. Particles of matter have force acting between them.
Which of the statements given above is/are correct?

Correct Answer: (c) Both 1 and 2
Solution:

Particles of matter intermix on their own. Particles of matter attract each other. The force of attraction, responsible for keeping them close is inter-molecular force of attraction.
Hence, statement 1 and 2 both are correct.

5. Rate of evaporation increases with [Evening Shift-2019 (II)]

Correct Answer: (a) an increase of surface area
Solution:

The rate of evaporation increases on increasing the surface area of the liquid. If the surface area is increased, the rate of evaporation increases.

6. Consider the following statements about mixture : [Evening Shift-2019 (II)]

1. A substance can be separated into other kinds of matter by any physical process.
2. Dissolved sodium chloride can be separated from water by the physical process of evaporation.
Which of the statements given above is/are correct?

Correct Answer: (b) Only 2
Solution:

In order to separate the components of mixture, single or a combination of methods are used to separation of mixture can be done by both physical and chemical process. So, statement 1 is incorrect.
Dissolved sodium chloride can be separated from water by evaporation. This method is used to separate a volatile component from a non-volatile component of a mixture. So, statement 2 is correct.

7. Which one of the following option is incorrect? [Evening Shift-2019 (II)]

Correct Answer: (b) Isobars are atoms having the same atomic number, but different mass number.
Solution:

Atoms of different elements with different atomic numbers, but same mass number are known as isobars.
Hence, option (b) is in correct.

8. Which one of the following is mono atomic? [Evening Shift-2019 (II)]

Correct Answer: (d) Helium
Solution:Elements    Atomicity
● Hydrogen    Diatomic
● Sulphur    Polyatomic
● Phosphorus    Tetra atomic
● Helium    Mono atomic
Hence, helium is mono atomic among given options.

9. In graphite, each carbon atom is bonded to three other carbon atoms [Evening Shift-2019 (II)]

Correct Answer: (b) in the same plane giving a hexagonal array
Solution:

In graphite, each carbon atom is bonded to three other carbon atoms in the same plane given a hexagonal array. The fourth electron of each carbon atom is free.

10. Employing chromatography, one cannot separate [Evening Shift-2019 (II)]

Correct Answer: (a) radioisotopes
Solution:

Chromatography is the technique for the separation of those solvents, that dissolve in the same solvent. Radioisotopes cannot be dissolve in the same solvent to separate it.