Chemistry · NDA previous year questions

The mass number of argon is 40. Which one of the following statements is correct?

1. A.The number of protons in argon is 22.
2. B.The number of neutrons in argon is 18.
3. C.The number of electrons in argon is 18.
4. D.The sum of numbers of protons and electrons in argon is 40.

Which one of the following is the correct order of the valencies of elements Ne, Si, N and Mg?

1. A.Ne < Mg < N < Si
2. B.Si < N < Mg < Ne
3. C.Ne < N < Si < Mg
4. D.Mg < Ne < N < Si

Which one of the following reactions is an example of decomposition reaction?

1. A.$\mathrm{C}{\mathrm{H}}_4(\mathrm{g})+2{\mathrm{O}}_2(\mathrm{g})\to \mathrm{C}{\mathrm{O}}_2(\mathrm{g})+2{\mathrm{H}}_2\mathrm{O}(\mathrm{g})$
2. B.$2AgCl(\mathrm{s})\stackrel{\mathrm{Sunlight}}{\to }2Ag(\mathrm{s})+\mathrm{C}{\mathrm{l}}_2(\mathrm{g})$
3. C.$\mathrm{CuO}+{\mathrm{H}}_2\stackrel{\mathrm{Heat}}{\to }\mathrm{Cu}+{\mathrm{H}}_2\mathrm{O}$
4. D.$\mathrm{Fe}(\mathrm{s})+\mathrm{CuS}{\mathrm{O}}_4(\mathrm{aq})\to \mathrm{FeS}{\mathrm{O}}_4(\mathrm{aq})+\mathrm{Cu}(\mathrm{s})$

Why are the tyres of aircrafts made of conducting rubber? 1. So that the charge accumulated on the aircraft in flight, by rubbing the air, can easily be transferred to ground on landing. 2. So that the charge accumulated due to the operation of various electronic equipments in the aircraft in flight can easily be transferred to ground on landing. Select the correct answer using the code given below.

1. A.1 only
2. B.2 only
3. C.Both 1 and 2
4. D.Neither 1 nor 2

The pH value of Milk of Magnesia is approximately

1. A.zero
2. B.7
3. C.10
4. D.14

MCQ (More than One Correct Answer) Which one of the following compounds is used in ‘black and white’ photography ?

1. A.$\mathrm{AgF}$
2. B.$\mathrm{AgBr}$
3. C.$\mathrm{AgCl}$
4. D.$\mathrm{A}{\mathrm{g}}_2\mathrm{S}{\mathrm{O}}_4$

What is the number of water molecules present in a Ferrous Sulphate crystal ?

1. A.1
2. B.3
3. C.5
4. D.7

What is the colour of the precipitate obtained by passing $\mathrm{C}{\mathrm{O}}_2$ gas through lime water ?

1. A.Green
2. B.Blue
3. C.White
4. D.Brown

Which one of the following pairs of elements is liquid at room temperature and at normal pressure ?

1. A.Gallium and Bromine
2. B.Mercury and Bromine
3. C.Gallium and Mercury
4. D.Gallium and Caesium

Which one of the following methods can be used to separate anthracene from a mixture of salt and anthracene ?

1. A.Distillation
2. B.Sublimation
3. C.Evaporation
4. D.Chromatography

Rutherford’s alpha-particle (α) scattering experiment was responsible for the discovery of which one of the following?

1. A.Electron
2. B.Proton
3. C.Atomic Nucleus
4. D.Neutron

What is the maximum number of electrons in the M-Shell ?

1. A.6
2. B.8
3. C.18
4. D.32

Chlorine occurs in nature in two isotopic forms of masses 35 u and 37 u in the ratio of 3 ∶ 1 respectively. What is the average atomic mass of the Chlorine atom ?

1. A.36.1 u
2. B.35.5 u
3. C.36.5 u
4. D.35.1 u

Which one of the following elements’ isotopes is used in the treatment of cancer ?

1. A.Iodine
2. B.Sodium
3. C.Cobalt
4. D.Uranium

To protect steel and iron from rusting, a thin layer of which one of the following metals is applied ?

1. A.Magnesium
2. B.Zinc
3. C.Aluminium
4. D.Lead

Which one of the following ions is not iso-electronic with ${\mathrm{F}}^{-}$ ?

1. A.${\mathrm{O}}^{2-}$
2. B.$\mathrm{N}{\mathrm{a}}^{+}$
3. C.$\mathrm{Ne}$
4. D.${\mathrm{N}}^{-}$

Which one of the following is the chemical formula of Plaster of Paris ?

1. A.$\mathrm{CaS}{\mathrm{O}}_4\cdot \frac{1}{2}{\mathrm{H}}_2\mathrm{O}$
2. B.$\mathrm{CaS}{\mathrm{O}}_4\cdot 2{\mathrm{H}}_2\mathrm{O}$
3. C.$\mathrm{CaS}{\mathrm{O}}_4\cdot 5{\mathrm{H}}_2\mathrm{O}$
4. D.$\mathrm{CaS}{\mathrm{O}}_4\cdot 4{\mathrm{H}}_2\mathrm{O}$

Common salt (NaCl) is not used as a raw material for preparation of which one of the following compounds?

1. A.Bleaching powder
2. B.Baking soda
3. C.Plaster of Paris
4. D.Washing soda

Which one of the following is the chemical formula of Hypobromous acid?

1. A.$\mathrm{HBr}{\mathrm{O}}_4$
2. B.$\mathrm{HOBr}$
3. C.$\mathrm{HBr}$
4. D.$\mathrm{HBr}{\mathrm{O}}_3$

The composition of gases in exosphere is

1. A.Helium and Hydrogen.
2. B.Neon and Oxygen.
3. C.Neon and Hydrogen.
4. D.Helium and Neon.

In electrolytic refining of copper, the electrolyte is a solution of

1. A.Acidified copper chloride.
2. B.Acidified copper sulphate.
3. C.Potassium chloride.
4. D.Sodium sulphate.

Which one of the following statements about dihydrogen (${\mathrm{H}}_2$) is not correct?

1. A.${\mathrm{H}}_2$ is lighter than air and insoluble in water.
2. B.${\mathrm{H}}_2$ is inert at room temperature due to high $\mathrm{H}-\mathrm{H}$ bond dissociation enthalpy.
3. C.${\mathrm{H}}_2$ reacts with alkali metals at high temperature to yield metal hydrides.
4. D.A mixture of $\mathrm{N}{\mathrm{O}}_2$ and ${\mathrm{H}}_2$ is known as Syngas.

Which of the following sets of elements has the same valency?

1. A.Na, Mg, Ca
2. B.Na, Mg, Al
3. C.Mg, Ca, K
4. D.Mg, Ca, Ba

The process whereby certain minerals absorb water, expand and change is called as

1. A.Hydration
2. B.Oxidation
3. C.Hydrolysis
4. D.Carbonation

Hydrogenation of vegetable oils using nickel catalyst is an example of

1. A.Substitution reaction
2. B.Elimination reaction
3. C.Addition reaction
4. D.Free-radical polymerization