Chemistry · NDA previous year questions

The nucleus of a singly ionized carbon atom contains

1. A.6 protons and 6 neutrons
2. B.5 protons and 6 neutrons
3. C.6 protons, 6 neutrons and 6 electrons
4. D.12 protons, 6 neutrons and 6 electrons

The following equation is an example of a redox reaction, in which $\mathrm{C}{\mathrm{l}}_2$ is the oxidizing agent and $\mathrm{FeB}{\mathrm{r}}_3$ is the reducing agent : $$2\mathrm{FeB}{\mathrm{r}}_3(\mathrm{aq})+3\mathrm{C}{\mathrm{l}}_2(\mathrm{g})=2\mathrm{FeC}{\mathrm{l}}_3(\mathrm{aq})+3\mathrm{B}{\mathrm{r}}_2(\mathrm{l})$$ Which one among the following statements is _**incorrect**_ for this redox reaction?

1. A.Oxidizing agents are themselves reduced
2. B.Reducing agents gain or appear to gain electrons
3. C.Reducing agents are themselves oxidized
4. D.Oxidizing agents oxidize other substances

Which one among the following nitrogen compounds has the least percentage of nitrogen by mass?

1. A.$(\mathrm{N}{\mathrm{H}}_4{)}_3\mathrm{P}{\mathrm{O}}_4$
2. B.$\mathrm{N}{\mathrm{H}}_3$
3. C.$\mathrm{N}{\mathrm{H}}_4\mathrm{OH}$
4. D.$\mathrm{N}{\mathrm{H}}_4\mathrm{N}{\mathrm{O}}_3$

Which one among the following is the correct order of amount of lime ($\mathrm{CaO}$), silica ($\mathrm{Si}{\mathrm{O}}_2$), alumina ($\mathrm{A}{\mathrm{l}}_2{\mathrm{O}}_3$) and ferric oxide ($\mathrm{F}{\mathrm{e}}_2{\mathrm{O}}_3$) in Portland cement?

1. A.$\mathrm{CaO}>\mathrm{Si}{\mathrm{O}}_2>\mathrm{A}{\mathrm{l}}_2{\mathrm{O}}_3>\mathrm{F}{\mathrm{e}}_2{\mathrm{O}}_3$
2. B.$\mathrm{Si}{\mathrm{O}}_2>\mathrm{CaO}>\mathrm{F}{\mathrm{e}}_2{\mathrm{O}}_3>\mathrm{A}{\mathrm{l}}_2{\mathrm{O}}_3$
3. C.$\mathrm{A}{\mathrm{l}}_2{\mathrm{O}}_3>\mathrm{Si}{\mathrm{O}}_2>\mathrm{CaO}>\mathrm{F}{\mathrm{e}}_2{\mathrm{O}}_3$
4. D.$\mathrm{F}{\mathrm{e}}_2{\mathrm{O}}_3>\mathrm{A}{\mathrm{l}}_2{\mathrm{O}}_3>\mathrm{Si}{\mathrm{O}}_2>\mathrm{CaO}$

Which one among the following transitions of electron of hydrogen atom emits radiation of the shortest wavelength?

1. A.$n=2$ to $n=1$
2. B.$n=3$ to $n=2$
3. C.$n=4$ to $n=3$
4. D.$n=5$ to $n=4$

Which one among the following is the most appropriate statement with respect to the atomic weight of an element?

1. A.The atomic weight of an element is the sum total of the number of protons and neutrons present in the atom of the element
2. B.Unlike mass number, the atomic weight of an element can be a fraction
3. C.The atomic weight of an element is a whole number
4. D.The atomic weight of all the atoms in an element is the same

Two metallic wires A and B are of same material and have equal length. If the cross-sectional area of B is double that of A, then which one among the following is the electrical resistance of B?

1. A.Twice that of A
2. B.4 times that of A
3. C.$\frac{1}{4}$ that of A
4. D.$\frac{1}{2}$ that of A

Which one among the following is the major constituent of soda lime glass?

1. A.Sodium oxide
2. B.Calcium oxide
3. C.Calcium carbonate
4. D.Silica

Directions : The following items consist of two statements, Statement I and Statement II. You are to examine these two statements carefully and select the answers to these items using the code given below : Statement I : Water (${\text{H}}_2\text{O}$) is more polar than Hydrogen Sulphide (${\text{H}}_2\text{S}$). Statement II : Oxygen is more electronegative than Sulphur.

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 : Metal ions are Lewis acids. Statement II : Metal ions are electron pair acceptors.

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 : Diamond is very hard and has high melting point. Statement II : In diamond, each carbon is covalently bonded to four other carbon atoms to form a three-dimensional network.

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.

Bases turn red litmus blue and acids turn blue litmus red. A student tested a liquid with a red litmus paper and it stayed red with no change. This shows that the liquid

1. A.must be pure water
2. B.must be an acid
3. C.is not a base
4. D.is neither a base nor an acid

The main constituent of vinegar is

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

All the elements in a group (family) have a common valency. For example, all the elements of the carbon family (carbon, silicon, germanium, tin and lead) have common valency four. However, some of these elements can also have valency two. Which of the following can have valency two?

1. A.Silicon, germanium and tin
2. B.Only germanium and tin
3. C.Germanium, tin and lead
4. D.Only tin and lead

Match List I with List II and select the correct answer using the code given below the lists : List I (Metallic oxide) A. Uranium oxide B. Cuprous oxide C. Cobalt oxide D. Chromium oxide List II (Colour imparted to glass) 1. Red 2. Blue 3. Green 4. Yellow Code :

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

A neutral (unchanged) metal ball is suspended using a non-magnetic string. A positively charged insulating rod is placed near the ball which is observed to be attracted to the rod. This is because

1. A.the ball becomes positively charged by induction
2. B.the ball becomes negatively charged by induction
3. C.there is a rearrangement of the electrons in the ball
4. D.the number of electrons in the ball is more than the number of electrons on the rod

Which one among the following most correctly determines the atomic number of an element?

1. A.Number of protons
2. B.Number of protons and electrons
3. C.Number of ions
4. D.Number of nucleons

In oxidation 1. Hydrogen is displaced from a substance. 2. an electropositive element is added to or proportion of electropositive element increases in a substance. 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

When a copper rod is dipped in aqueous silver nitrate solution, the colour of the solution changes to blue. This is because

1. A.Cu is more easily reduced than Ag
2. B.Ag is more easily reduced than Cu
3. C.Nitrate ion acts as an oxidizing agent
4. D.Nitrate ion acts as a reducing agent

The reaction that takes place in soap making is called saponification. Basically soap is sodium or potassium salts of

1. A.long chain monocarboxylic acids
2. B.glycerol
3. C.long chain dicarboxylic acids
4. D.long chain tricarboxylic acids

The number of protons in a negatively charged atom (anion) is

1. A.more than the atomic number of the element
2. B.less than the atomic number of the element
3. C.more than the number of electrons in the atom
4. D.less than the number of electrons in the atom

The metal constituent of chlorophyll is

1. A.Iron
2. B.Potassium
3. C.Manganese
4. D.Magnesium

During explosion of gunpowder, which of the following gases are evolved in the proportion of 1 : 3?

1. A.Oxygen : Nitrogen
2. B.Nitrogen : Oxygen
3. C.Nitrogen : Carbon dioxide
4. D.Carbon dioxide : Nitrogen

Which one among the following statements is not correct?

1. A.In progressive waves, the amplitude may be constant and neighbouring points are out of phase with each other
2. B.In air or other gases, a progressive antinode occurs at a displacement node and a progressive node occurs at a displacement antinode
3. C.Transverse wave can be polarized while longitudinal wave can not be polarized
4. D.Longitudinal wave can be polarized while transverse wave can not be polarized

Glass is actually :

1. A.a crystalline solid.
2. B.an ionic solid.
3. C.an elastic solid.
4. D.a vitrified liquid.