NDA Chemistry Previous Year Questions

Consider the following statement :

"Acids are substances that dissociate in water to give hydrogen ions H^+ (aq), and bases are substances that produce hydroxyl ions OH^- (aq)."

The above statement is based on which one of the following concepts?

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

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?

A non-volatile solid solute may be separated from a solution by which of the following processes?

I. Evaporation

II. Crystallization

Consider the following:

I. $AlC{l}_3$

II. $N{H}_3$

III. $B{F}_3$

IV. $FeC{l}_3$

How many of the above are Lewis acids?

Consider the following statements:

I. Soaps are sodium or potassium salts of long-chain carboxylic acids.

II. The properties of catenation and isomerism in the element carbon are attributed to existence of large number of organic compounds than inorganic compounds.

III. Carbon dioxide is acidic but carbon monoxide is neutral molecule.

Which of the statements given above are correct?

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

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

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

Consider the following statements :

I. A colloid and a suspension are heterogeneous mixtures.

II. Colloids can be separated from the mixture by the process of centrifugation.

III. Particles of colloids and suspensions can be seen by naked eye.

IV. The aqueous solution of copper sulphate does not show Tyndall effect; however, the mixture of milk and water shows Tyndall effect.

Which of the statements given above is/are correct?

Consider the following pairs:

I. Pigment : TiO2
II. Drier : Turpentine
III. Thinner : Naphthenates
IV. Antiskinning agent : Polyhydroxy phenol

How many of the pairs given above are correctly matched?

Consider the following pairs of reactions and properties:

Reactions:

I. $Fe(s)+2HCl(aq)\to FeC{l}_2(aq)+H_2(g)$

II. $Zn(s)+CuS{O}_4(aq)\to ZnS{O}_4(aq)+Cu(s)$

III. $B{r}_2(l)+2I^{-}(aq)\to 2B{r}^{-}(aq)+I_2(s)$

IV. $C{H}_4(g)+2O_2(g)\to C{O}_2(g)+2H_{2}O(l)$

Properties:

I. Fe is reductant

II. Cu is being reduced

III. Br_2 is reductant

IV. C atom in $C{H}_4$ is oxidized

Which of the above pairs are correct?

Which of the following is/are the physical test(s) employed for the manufacture of paper?

I. Mechanical and strength properties

II. Surface properties

III. Optical properties

IV. Permeability to fluids

Select the correct answer using the code given below.

Which of the following statements is/are correct with regard to Nitrolim?

I. It is prepared by heating calcium carbide with nitrogen.
II. It decomposes into ammonia in soil.
III. It is an NPK fertilizer.
IV. It is an organic fertilizer.

Select the answer using the code given below.

Consider the following statements:

I. Pine oil is used as antifoaming agent in the emulsion paints.
II. Protective colloids are used in the emulsion paints to decrease their stability.
III. Driers having oxidizable oils are added to the emulsion paints to accelerate drying process.

Which of the statements given above is/are correct?