Chemistry (CDS-Solved Paper)

Total Questions: 50

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

‘‘Atomic number of an element is a more fundamental property than its atomic mass.’’ Who among the following scientists has made the above statement?

Correct Answer: (b) Henry Moseley
Solution:

Given statement was stated by Henry Moseley. Mendeleev’s periodic table was, therefore accordingly modified.

12. Very small insoluble particles in a liquid may be separated from it by using [Morning Shift-2019 (I)]

Correct Answer: (d) decantation
Solution:

There are some mixtures which contain insoluble solid particles suspended in a liquid. The solid particles which are insoluble in a liquid can be separated by using decantation method.

13. In which of the following, functional group isomerism is not possible? [Morning Shift-2019 (I)]

Correct Answer: (a) Alcohols
Solution:

In alkyl halides, functional group isomerism is not possible. Rest of all options show functional group isomerism.

14. Which one of the following statements is not correct? [Morning Shift-2019 (I)]

Correct Answer: (c) Fischer projection of the molecule is its most stable conformation.
Solution:

Statement is given in option (c) is correct. Correct statements is Fischer projection always depicts, the molecule in eclipsed form, hence it is most stable conformation.

15. The monomer/monomers used for the synthesis of nylon 6 is/are [Morning Shift-2019 (I)]

Correct Answer: (b) caprolactam
Solution:

Nylon 6 is only made from one kind of monomer, a monomer is called caprolactam.

16. When hot water is placed into an empty water bottle, the bottle keeps its shape and does not soften. What type of plastic is the water bottle made from ? [Morning Shift-2019 (I)]

Correct Answer: (d) Thermosetting
Solution:

Water bottle made from thermosetting plastics. Thermosetting plastic is a polymer that irreversibly becomes rigid when heated. Also known as thermoset, thermosetting polymer.

17. Which of the following is/are state function/functions? [Morning Shift-2019 (I)]

1. q W+
2. q
3. W
4. H - TS

Correct Answer: (a) 1 and 4
Solution:

Internal energy (∆E) = + q W .
It is a state function because it is independent of the path.
● Gibbs energy (G) = H − TS
It is also a state function because it is independent of the path.
Heat (q) and work (W ) are not state functions being path dependent.

18. For a certain reaction,

∆G⁻ = - 45 kJ/mol and
∆H⁻ = - 90KJ/mol at 0°C.
What is the minimum temperature at which the reaction will become spontaneous, assuming that ∆H⁻ and ∆S⁻ are independent of temperature?

Correct Answer: (a) 273 K
Solution:

∵ ∆G = ∆H − T S∆ and ∆H and ∆S are independent of temperature,

19. The PCl₅ molecule has trigonal bipyramidal structure. Therefore, the hybridisation of p-orbitals should be [Morning Shift-2019 (I)]

Correct Answer: (d) dsp³
Solution:

Phosphorus has five electrons in valence orbitals, which can hybridised and give five hybrid orbitals, viz. Three p-orbitals one each of s-and d-orbitals. Thus, hybridisation of P in PCl₅ is sp³d .

20. For an ideal gas, which one of the following statements does not hold true? [Morning Shift-2019 (I)]

Correct Answer: (a) The speed of all gas molecules is same.
Solution:

Statement (a) is incorrect, because an ideal gas consist of a very large number of molecules which are in a state of continuous, rapid and random motion. They move in all direction with different speeds, ranging from zero to infinity, this is a postulate of an ideal gas.