Chemistry · NDA previous year questions

The symbol of the element ‘Tungsten’ is:

1. A.Ta
2. B.W
3. C.Tl
4. D.Tc

Which one of the following statements is correct?

1. A.Rutherford’s alpha-particle scattering experiment led to the discovery of electron
2. B.J J Thomson suggested that the nucleus of an atom contains protons
3. C.The atomic number of an element is the same as the number of protons in the nucleus of its atom
4. D.The mass number of an atom is equal to the number of electrons in its shells

The alkali metals have relatively low melting point. Which one of the following alkali metals is expected to have the highest melting point?

1. A.Li
2. B.Na
3. C.K
4. D.Rb

Consider the following reaction: $${\text{CH}}_4(\text{g})+{\text{H}}_2\text{O}(\text{g})\stackrel{1270\text{ K}}{\to }\text{CO}(\text{g})+3{\text{H}}_2(\text{g})$$ In the reaction given above, the mixture of $\text{CO}$ and ${\text{H}}_2$ is:

1. A.natural gas
2. B.water gas
3. C.producer gas
4. D.industrial gas

To weld metals together, high temperature is required. Such a high temperature is obtained by burning:

1. A.Acetylene in oxygen
2. B.LPG in oxygen
3. C.Methane in oxygen
4. D.Acetylene in nitrogen

Boric acid is an acid because its molecule:

1. A.accepts $\mathrm{O}{\mathrm{H}}^{-}$ from water releasing proton
2. B.combines with proton from water molecule
3. C.contains replaceable ${\mathrm{H}}^{+}$ ion
4. D.gives up a proton

The main constituent of Vinegar is:

1. A.Acetic acid
2. B.Ascorbic acid
3. C.Citric acid
4. D.Tartaric acid

Which of the following are the properties of an electron? 1. Electron is a constituent of cathode ray 2. Electron is a negatively charged particle 3. The mass of the electron is equal to the mass of the proton 4. Electron is deflected by the electric field but not by magnetic field Select the correct answer using the code given below:

1. A.1 and 2 only
2. B.1, 2 and 3
3. C.3 and 4
4. D.1 and 4

Which of the following statements regarding heavy water are correct? 1. It is extensively used as a moderator in nuclear reactors 2. It cannot be used in exchange reaction to study reaction mechanism 3. Viscosity of heavy water is relatively smaller than that of ordinary water 4. The dielectric constant of heavy water is smaller than that of ordinary water Select the correct answer using the code given below:

1. A.1 and 2
2. B.2 and 3
3. C.3 and 4
4. D.1 and 4

Graphite is a much better conductor of heat and electricity than diamond. This is due to the fact that each carbon atom in graphite:

1. A.undergoes $\mathrm{s}{\mathrm{p}}^2$ hybridization and forms three sigma bonds with three neighbouring carbon atoms
2. B.undergoes $\mathrm{s}{\mathrm{p}}^3$ hybridization
3. C.is tetrahedrally bonded
4. D.is free from van der Waals force

Which one of the following is not a Green House Gas?

1. A.Water vapours
2. B.Methane
3. C.Ozone
4. D.Carbon Monoxide

Muscle fatigue is due to the accumulation of:

1. A.Cholesterol
2. B.Lactic acid
3. C.Lipoic acid
4. D.Triglycerides

Which one of the following circuit elements is an active component?

1. A.Resistor
2. B.Transistor
3. C.Inductor
4. D.Capacitor

The working of a microwave oven involves

1. A.absorption of microwaves by matter
2. B.reception of microwaves by optical fibre
3. C.microwave amplification by stimulated emission of radiation
4. D.transmission of microwaves through a metal

A sample of carbon dioxide that undergoes a transformation from solid to liquid and then to gas would undergo

1. A.a change in mass
2. B.a change in density
3. C.a change in composition
4. D.no change in physical properties

Which of the following element combinations will form ionic compounds? 1. Ca $(Z=20)$ and Ti $(Z=22)$ 2. Si $(Z=14)$ and Br $(Z=35)$ 3. Mg $(Z=12)$ and Cl $(Z=17)$ Select the correct answer using the code given below.

1. A.2 only
2. B.3 only
3. C.2 and 3 only
4. D.1, 2 and 3

A compound ${\mathrm{X}}_2{\mathrm{O}}_3$ contains 31.58% oxygen by weight. The atomic mass of X is

1. A.$34.66\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}$
2. B.$45.01\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}$
3. C.$52.00\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}$
4. D.$104.00\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}$

The burning sensation of a beesting can be stopped by rubbing the affected area with soap. This is because

1. A.a beesting is acidic and soap, an alkali, neutralizes it
2. B.a beesting is alkaline and soap, an acid, neutralizes it
3. C.soap cleans the affected area and removes the sting
4. D.soap acts as an anesthetic and dulls the sensation

A sample of gas is to be identified by means of its behaviour in the presence of a glowing splint. Which of the following gases will neither itself burn nor cause the splint to burn?

1. A.Oxygen
2. B.Nitrogen
3. C.Hydrogen
4. D.Methane

Consider the following reaction : $$x\mathrm{A}{\mathrm{s}}_2{\mathrm{S}}_3+y{\mathrm{O}}_2\to z\mathrm{A}{\mathrm{s}}_2{\mathrm{O}}_3+w\mathrm{S}{\mathrm{O}}_2$$ What is $y$ (the coefficient for ${\mathrm{O}}_2$) when this equation is balanced using whole number coefficients?

1. A.5
2. B.7
3. C.9
4. D.11

If the reaction of $1.0\mathrm{mol}\mathrm{N}{\mathrm{H}}_3(\mathrm{g})$ and $1.0\mathrm{mol}{\mathrm{O}}_2(\mathrm{g})$ $$4\mathrm{N}{\mathrm{H}}_3(\mathrm{g})+5{\mathrm{O}}_2(\mathrm{g})\to 4\mathrm{NO}(\mathrm{g})+6{\mathrm{H}}_2\mathrm{O}(l)$$ is carried to completion, then

1. A.all the ${\mathrm{O}}_2(\mathrm{g})$ is consumed
2. B.$4.0\mathrm{mol}\mathrm{NO}(\mathrm{g})$ is produced
3. C.$1.5\mathrm{mol}{\mathrm{H}}_2\mathrm{O}(l)$ is produced
4. D.all the $\mathrm{N}{\mathrm{H}}_3(\mathrm{g})$ is consumed

The very high heat of vaporization of water is mainly a result of

1. A.van der Waals forces
2. B.covalent bonds
3. C.interionic attraction
4. D.hydrogen bonding

A monatomic species that has 18 electrons and a net charge of $2^{-}$ has

1. A.the same number of electrons as a neutral argon atom
2. B.more protons than electrons
3. C.2 unpaired electrons
4. D.20 protons

Statement II: Glass does not have a definite melting point.

1. A.Both the statements are individually true and Statement II is the correct explanation of Statement I
2. B.Both the Statements are individually true but Statement II is not the correct explanation of Statement I
3. C.Statement I is true but Statement II is false
4. D.Statement I is false but Statement II is true

Statement I: Limestone decomposes when it is heated in air. Statement II: Increase in the content of $\mathrm{C}{\mathrm{O}}_2$ in the atmosphere in recent years is mainly due to the using of limestone in the manufacture of cement.

1. A.Both the statements are individually true and Statement II is the correct explanation of Statement I
2. B.Both the Statements are individually true but Statement II is not the correct explanation of Statement I
3. C.Statement I is true but Statement II is false
4. D.Statement I is false but Statement II is true