Chemistry · NDA previous year questions

Consider the following statements regarding oxidation numbers: I. The oxidation number of oxygen in peroxides and superoxides is assigned as $-1$ and $-1/2$ respectively. II. In all its compounds, fluorine has an oxidation number of $-1$. III. In a reduction half-reaction, the oxidation number of the reductant decreases. Which of the statements given above are correct?

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

Consider the following statements regarding the properties of hydrogen and water: I. Tritium, the isotope of hydrogen, is radioactive and emits low energy alpha particles. II. In the gas phase, the structure of water is linear. III. The basic principle of a hydrogen economy is the transportation and storage of energy in the form of liquid or gaseous molecular hydrogen. Which of the statements given above is/are not correct?

1. A.I and II only
2. B.II and III only
3. C.I and III only
4. D.II only

Consider the following statements regarding nitrogen: I. Nitrogen contains a triple bond. II. Nitrogen is a triatomic gas. III. Forces acting between nitrogen molecules are weak van der Waals forces. Which of the statements given above are correct?

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

Consider the following statements: I. Zinc metal, when treated with both HCl (aq.) and NaOH (aq.) separately, produces molecular hydrogen. II. An aqueous copper sulphate solution cannot be kept in a zinc vessel. III. Lemon, tamarind and tomato are natural sources of citric acid, oxalic acid and tartaric acid, respectively. Which of the statements given above are correct?

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

Consider the following statements: I. A $30\%$ solution of hydrogen peroxide is marketed as `10 volume' ${\mathrm{H}}_2{\mathrm{O}}_2$. II. In the compound copper sulphate pentahydrate, all the five water molecules are hydrogen bonded. Which of the statements given above is/are correct?

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

Consider the following pairs: $$\begin{array}{lll}& \text{Chemical Reaction}& \text{Type of Chemical Reaction}\\ \text{I.}& \mathrm{Fe}(\mathrm{s})+\mathrm{CuS}{\mathrm{O}}_4(aq.)\to \mathrm{FeS}{\mathrm{O}}_4(aq.)+\mathrm{Cu}(\mathrm{s})& \text{Displacement reaction}\\ \text{II.}& \mathrm{N}{\mathrm{a}}_2\mathrm{S}{\mathrm{O}}_4(aq.)+\mathrm{BaC}{\mathrm{l}}_2(aq.)\to \mathrm{BaS}{\mathrm{O}}_4(\mathrm{s})+2NaCl(aq.)& \text{Double displacement reaction}\\ \text{III.}& \mathrm{F}{\mathrm{e}}_2{\mathrm{O}}_3(\mathrm{s})+3CO(\mathrm{g})\to 2Fe(\mathrm{s})+3C{\mathrm{O}}_2(\mathrm{g})& \text{Redox reaction}\\ \text{IV.}& 2KCl{\mathrm{O}}_3(\mathrm{s})\to 2KCl(\mathrm{s})+3{\mathrm{O}}_2(\mathrm{g})& \text{Thermal decomposition reaction}\end{array}$$ How many of the pairs given above are correctly matched?

1. A.One
2. B.Two
3. C.Three
4. D.All four

Coconut oil upon hydrolysis with potassium hydroxide gives:

1. A.Free fatty acids and sodium hydroxide
2. B.Glycerol and sodium salts of fatty acids
3. C.Glycol and potassium salts of fatty acids
4. D.Glycerol and potassium salts of fatty acids

Consider the following statements regarding hydrogen bonds: I. Hydrogen bonds can only form when hydrogen is bonded to oxygen, nitrogen or fluorine. II. Hydrogen bonds are intramolecular only. III. The strength of a hydrogen bond decreases with a decrease in the electronegativity of the two bonded atoms. Which of the statements given above is/are not correct?

1. A.I only
2. B.II only
3. C.I and II
4. D.II and III

Ionic compounds have high melting and boiling points. This is due to:

1. A.the presence of strong electrostatic forces between ions in the crystal lattice.
2. B.the weak intermolecular van der Waals forces.
3. C.the presence of a ‘sea of delocalized electrons’.
4. D.lower lattice energy.

Consider the following pairs of reactions and properties: $$\begin{array}{ll}\text{Reactions}& \text{Properties}\\ \text{I. }\mathrm{Fe}(\mathrm{s})+2HCl(\mathrm{aq})\to \mathrm{FeC}{\mathrm{l}}_2(\mathrm{aq})+{\mathrm{H}}_2(\mathrm{g})& \mathrm{Fe}\text{ is reductant}\\ \text{II. }\mathrm{Zn}(\mathrm{s})+\mathrm{CuS}{\mathrm{O}}_4(\mathrm{aq})\to \mathrm{ZnS}{\mathrm{O}}_4(\mathrm{aq})+\mathrm{Cu}(\mathrm{s})& \mathrm{Cu}\text{ is being reduced}\\ \text{III. }\mathrm{B}{\mathrm{r}}_2(\mathrm{l})+2{\mathrm{I}}^{-}(\mathrm{aq})\to 2B{\mathrm{r}}^{-}(\mathrm{aq})+{\mathrm{I}}_2(\mathrm{s})& \mathrm{B}{\mathrm{r}}_2\text{ is reductant}\\ \text{IV. }\mathrm{C}{\mathrm{H}}_4(\mathrm{g})+2{\mathrm{O}}_2(\mathrm{g})\to \mathrm{C}{\mathrm{O}}_2(\mathrm{g})+2{\mathrm{H}}_2\mathrm{O}(\mathrm{l})& \mathrm{C}\text{ atom in }\mathrm{C}{\mathrm{H}}_4\text{ is oxidized}\end{array}$$ Which of the above pairs are correct?

1. A.I and II only
2. B.II, III and IV
3. C.I, II and IV
4. D.I, III and IV

Consider the following: I. $\mathrm{AlC}{\mathrm{l}}_3$ II. $\mathrm{N}{\mathrm{H}}_3$ III. $\mathrm{B}{\mathrm{F}}_3$ IV. $\mathrm{FeC}{\mathrm{l}}_3$ How many of the above are Lewis acids?

1. A.One
2. B.Two
3. C.Three
4. D.All the four

$1.7\mathrm{g}$ of silver nitrate is dissolved in $100\mathrm{g}$ of water, and $0.585\mathrm{g}$ of sodium chloride is dissolved in $100\mathrm{g}$ of water. Both are mixed and a chemical reaction occurs. $1.435\mathrm{g}$ of silver chloride and $0.85\mathrm{g}$ of sodium nitrate are formed. Which law of chemical combination is shown by the above reaction?

1. A.Law of multiple proportions
2. B.Law of conservation of mass
3. C.Law of reciprocal proportions
4. D.Law of constant proportions

Superphosphate of lime, a phosphate fertilizer, is obtained by the reaction of

1. A.calcium phosphate with sodium hydroxide
2. B.calcium phosphate with sulphuric acid
3. C.calcium phosphate with hydrogen chloride
4. D.calcium phosphate with nitric acid

Consider the following statement: 'Acids are substances that dissociate in water to give hydrogen ions ${\mathrm{H}}^{+}$ (aq), and bases are substances that produce hydroxyl ions $\mathrm{O}{\mathrm{H}}^{-}$ (aq).' The above statement is based on which one of the following concepts?

1. A.Bronsted-Lowry concept
2. B.Lewis acid-base concept
3. C.Arrhenius concept
4. D.Conjugate acid-base concept

Which of the following are oxidation reactions? I. Rusting of iron II. Burning of fuel III. Rancidity of oils and fats IV. Browning of fruits Select the correct answer using the code given below.

1. A.I, II and III only
2. B.I, II and IV only
3. C.III and IV only
4. D.I, II, III and IV

Which one of the following forms of carbon is thermodynamically most stable?

1. A.Coal
2. B.Graphite
3. C.Diamond
4. D.Fullerene

If $x$ is the number of electrons and $y$ is the number of nucleons present in ${}_{16}^{32}{\mathrm{S}}^{2-}$, then which one of the following is correct?

1. A.$x=14$ and $y=32$
2. B.$x=16$ and $y=30$
3. C.$x=18$ and $y=32$
4. D.$x=18$ and $y=30$

A person jumps from a height on soft sand. Which one of the following is the correct reason for less likely injury to the person?

1. A.The sand exerts no reaction force.
2. B.The sand reduces the change in momentum.
3. C.The sand increases the impact time.
4. D.The sand increases the momentum.

A very large container consists of an ideal gas. The speed of sound in the gas is $x$. When the pressure of the gas is doubled while keeping the temperature constant, the speed of sound now becomes $y$. What is the ratio of $x$ to $y$?

1. A.1
2. B.$\sqrt{2}$
3. C.2
4. D.4

For an ideal gas, a process is described by $P=kT$, where $k$ is a constant. If the molar heat capacity for this process is $C$, then which one of the following is correct (where the symbols have their usual meanings)?

1. A.$C=C_P$
2. B.$C=C_V$
3. C.$C=(C_P+C_V)/2$
4. D.$C$ is never constant

In a certain process, the relation between pressure $(P)$ and volume $(V)$, for an ideal gas, is given by $P{V}^2=$ constant. If the initial temperature is $T_1$ and the final temperature is $T_2$; and the initial volume is $V_1$ and the final volume is $V_2$, then which one of the following is correct?

1. A.$\frac{T_1}{T_2}=\frac{V_1}{V_2}$
2. B.$\frac{T_1}{T_2}={\left(\frac{V_1}{V_2}\right)}^2$
3. C.$\frac{T_1}{T_2}=\frac{V_2}{V_1}$
4. D.$\frac{T_1}{T_2}={\left(\frac{V_2}{V_1}\right)}^2$

Consider the following statements in case of terrestrial planets: I. Mercury, Venus, Earth and Mars are terrestrial planets having low densities as compared to other planets. II. They lie between the Sun and the belt of asteroids. III. Their lower gravity can hold the escaping gases. Which of the statements given above is/are correct?

1. A.I and II
2. B.II and III
3. C.I and III
4. D.II only

Which one among the following statements is correct ?

1. A.Pressure has magnitude as well as direction
2. B.As we go deeper in a liquid, the pressure decreases
3. C.Action and reaction forces act on the same object
4. D.Pascal and $N/{\mathrm{m}}^2$ represent the same unit

The reaction that occurs on passing carbon dioxide gas through lime water is

1. A.$\mathrm{CaC}{\mathrm{O}}_3+{\mathrm{H}}_2\mathrm{O}+\mathrm{C}{\mathrm{O}}_2\to \mathrm{Ca}(\mathrm{HC}{\mathrm{O}}_3{)}_2$
2. B.$\mathrm{Ca}(\mathrm{OH}{)}_2+\mathrm{C}{\mathrm{O}}_2\to \mathrm{CaC}{\mathrm{O}}_3+{\mathrm{H}}_2\mathrm{O}$
3. C.$\mathrm{CaO}+\mathrm{C}{\mathrm{O}}_2\to \mathrm{CaC}{\mathrm{O}}_3$
4. D.$\mathrm{CaC}{\mathrm{l}}_2+{\mathrm{H}}_2\mathrm{O}+\mathrm{C}{\mathrm{O}}_2\to \mathrm{CaC}{\mathrm{O}}_3+2HCl$

Which one of the following statements is NOT correct ?

1. A.Water of crystallization is the fixed number of water molecules present in one formula unit of a salt
2. B.The molecular formula of Plaster of Paris is $\mathrm{CaS}{\mathrm{O}}_4:2{\mathrm{H}}_2\mathrm{O}$
3. C.Washing soda is used for removing the permanent hardness of water
4. D.The atmosphere of Venus is made up of thick white and yellow clouds of sulphuric acid