NSEC 2024 24th Nov Question Paper

A closed vessel with rigid walls contains 1.0 mol of component M (vapour pressure $$p_M^*$$) present as 0.9 mol liquid and 0.1 mol vapour. 0.1 mol of component N (vapour pressure $$p_N^*$$) is added slowly to maintain equilibrium conditions. Assume M and N form an ideal solution. The total pressure at the end of the addition will

A scuba diver accidentally surfaces from a depth of 100 feet in water (pressure $$= 4$$ atm). The solubility of nitrogen from air (78% $$\text{N}_2$$ in air) in water in standard conditions is 15 mg $$\text{L}^{-1}$$ at $$37^\circ\text{C}$$. The volume of $$\text{N}_2$$ gas released into the bloodstream of the diver from each litre of blood is (assume blood to behave similarly as water)

A 35 degree drop in temperature from $$25^\circ\text{C}$$ causes a 8.2-fold decrease in the rate of a first order reaction. If the half-life of the reaction is 3.2 h, what will be the half-life at a temperature of $$-10^\circ\text{C}$$

An ideal-gas reaction equilibrium is represented as $$A + B \rightleftharpoons C + D$$. Considering the fact that all components are ideal and that only A and B are present initially, which of the following options is ALWAYS true at equilibrium, where $$N$$ is the number of moles of the species

Which of the following statements is correct

Consider the following statements about the mechanism whose steps are 

$$A + B \rightarrow C + D$$, 

$$2C \rightarrow F$$ and 

$$F + B \rightarrow 2A + G$$. Statement 

(i) is that the overall reaction is $$3B \rightarrow 2D + G$$. Statement 

(ii) is that A is a catalyst and B is a reactant. Statement 

(iii) is that C and F are intermediates. Statement 

(iv) is that D and G are products. The correct set of statements is

For one mole of a van der Waals gas with $$b = 0$$, the plot of $$PV$$ versus $$\frac{1}{V}$$ at 298 K gives an intercept of 24.4 L atm K $$\text{mol}^{-1}$$ and a slope of $$-2.5\ \text{L}^2\ \text{atm}\ \text{mol}^{-2}$$. The value of the van der Waals constant $$a$$ is

The following three plots show the variation of conductance with mL of titrant added for three titrations of aqueous solutions of $$\text{Na}_2\text{SO}_4$$, $$(\text{NH}_4)_2\text{SO}_4$$ and $$\text{BaCl}_2$$. The molar ionic conductivities in $$\text{S cm}^2\ \text{mol}^{-1}$$

Assign the plots to the respective titrations

150 g of liquid water at $$20^\circ\text{C}$$ is mixed with 40 g of ice at $$0^\circ\text{C}$$ in a coffee cup calorimeter. The final temperature in $$^\circ\text{C}$$ reached will be, assuming no heat loss or gain by the surroundings, given that the latent heat of ice is 334.72 J/g and the specific heat of water is 4.2 J/g $$^\circ\text{C}$$

A chemical reaction $$X(g) + Y(g) \rightarrow Z(g)$$ has the following mechanism. 

$$X(g) + S(s)$$ $$\rightleftharpoons$$ [X-S](s)$$ 

$$[X-S](s) + Y(g)$$ $$\rightleftharpoons$$ $$Z(g) + S(s)$$ ; [where (S) is solid catalyst]

 The overall equilibrium constant for the above reaction can be represented as

Given below is a galvanic cell $$\text{Cu}(s) \mid \text{Cu}^{2+}(aq)\ (x\ \text{M}) \parallel \text{Ag}^+(aq)\ (y\ \text{M}) \mid \text{Ag}(s)$$. The possible condition for the galvanic cell to develop an emf of 0.5 V is, given that $$E^\circ_{\text{Cu}^{2+}/\text{Cu}} = 0.34$$ V and $$E^\circ_{\text{Ag}^+/\text{Ag}} = 0.8$$ V

If 5 A current is passed for an hour through one $$\text{dm}^3$$ of 0.5 M aqueous solution of sodium acetate, then the amount of ethane produced will be

The results obtained when the finely divided metal powders of P, Q, R and S are added to the aqueous solutions of different metal nitrates are given below: 

Displacement = √, No reaction = x

[Given: $$E^\circ_{\text{Ag}^+/\text{Ag}} = 0.80$$ V, $$E^\circ_{\text{Zn}^{2+}/\text{Zn}} = -0.76$$ V, $$E^\circ_{\text{Ni}^{2+}/\text{Ni}} = -0.25$$ V and $$E^\circ_{\text{Pb}^{2+}/\text{Pb}} = -0.13$$ V].
If these elements are to be arranged as per their positions in the electrochemical series, then which of the following will represent the above set of observations

The molarity of the commercially available concentrated sulphuric acid solution with the label on the bottle as shown below is

Oxide ions with ions of metals A and B together form a crystal. The oxide ions get organized into a cubic closed packed (ccp) lattice. In the oxide lattice, the metal ion A occupies 25% of the octahedral voids and the metal ion B occupies 50% of the tetrahedral voids. Oxidation states of A and B respectively are

Consider the statements. 

 (i) is that the energy of the electron in the fourth orbit of $$\text{He}^+$$ ion is less than the energy of the electron in the fourth orbit of hydrogen atom. 

(ii) is that the radius of the first orbit of $$\text{He}^+$$ ion is 0.529 $$\text{\AA}$$. 

(iii) is that in the Lyman series, as the energy liberated during the transition increases the distance between the spectral lines goes on decreasing. 

(iv) is that if the radius of the 2nd orbit of $$\text{Li}^{2+}$$ is $$x$$, the expected radius of the 3rd orbit of $$\text{Be}^{3+}$$ is $$\frac{9}{4}x$$. 

(v) is that in the hydrogen atom, 3p and 3d orbitals are not degenerate orbitals. 

The correct set of statements is

The mixture of $$\text{Al(OH)}_3$$ and $$\text{Fe(OH)}_3$$ can be separated by :

(i) leaching, (ii) froth floatation, (iii) gravity separation and (iv) magnetic separation

The anions giving white precipitate completely soluble in concentrated hydrochloric acid with barium chloride solution are (i) sulphite, (ii) carbonate, (iii) sulphate and (iv) nitrate

The substituted silanes which can produce dimeric and cyclic trimeric silicone polymers, respectively, on hydrolysis are 1. $$\text{RSiCl}_3$$, 2. $$\text{R}_2\text{SiCl}_2$$ and 3. $$\text{R}_3\text{SiCl}$$

Identify the correct pair of species with the correct description

A student mixed three sodium salts accidentally. To identify these salts some tests were performed and it was found that 

(i) when the chromyl chloride test was performed a mixture of coloured gases was released and the NaOH solution turned yellow and gave a positive test, 

(ii) the brown ring test was positive but the brown coloured gas was not intensified on adding copper turnings on heating the mixture with concentrated $$\text{H}_2\text{SO}_4$$, 

(iii) an aqueous solution of the mixture was treated with $$\text{CHCl}_3$$ and chlorine water, and from this chloroform layer the layer test was performed, when a violet organic layer was first visible and then on more addition of concentrated $$\text{HNO}_3$$ it changed to orange yellow. The observations indicate the presence of

Total number of stereoisomers shown by the complex $$[\text{W(CO)}_4\{\text{P(OR)}_3\}\text{SR}']$$ where $$\text{R} = -\text{C}_6\text{H}_5$$ and $$\text{R}' = -\text{CH}_3$$

A, B and C are three complexes of chromium (III) with empirical formula $$\text{H}_{12}\text{O}_6\text{Cl}_3\text{Cr}$$. All the three complexes have water and chloride ions as ligands. When subjected to heating at $$200^\circ\text{C}$$ the mass of A was found to be constant, while that of B suffered a loss of 6.7%. When 2.66 g of C was treated with $$\text{AgNO}_3$$ it gave 1.43 g of AgCl. The complexes B and C are respectively, chosen from 

1. $$[\text{Cr(H}_2\text{O)}_6\text{Cl}_3]$$, 

2. $$[\text{Cr(H}_2\text{O)}_6]\text{Cl}_3$$,

3. $$[\text{Cr(H}_2\text{O)}_5\text{Cl}]\text{Cl}_2 \cdot \text{H}_2\text{O}$$, 

4. $$[\text{Cr(H}_2\text{O)}_4\text{Cl}_2]\text{Cl} \cdot 2\text{H}_2\text{O}$$ 

5. $$[\text{Cr(H}_2\text{O)}_3\text{Cl}_3] \cdot 3\text{H}_2\text{O}$$

126 g oxalic acid ($$\text{H}_2\text{C}_2\text{O}_4 \cdot 2\text{H}_2\text{O}$$) under acidic conditions will be oxidized by

(i) $$\frac{1}{3}$$ mole of $$\text{K}_2\text{Cr}_2\text{O}_7$$

(ii) $$\frac{5}{2}$$ mol $$\text{K}_2\text{Cr}_2\text{O}_7$$

(iii) $$\frac{1}{3}$$ mol $$\text{KMnO}_4$$ 

(iv) $$\frac{5}{2}$$ mol $$\text{KMnO}_4$$

A carbonyl complex of Iridium with electronic configuration $$[\text{Xe}]\ 4f^{14}\ 5d^7\ 6s^2$$ and with the formula $$\text{IrCl(CO)(PPh}_3)_2$$ is known as Vaska$$'$$s complex. Which of the following ligand substitutions will decrease the triple bond character of CO in Vaska$$'$$s complex

A water sample is analysed and found to have concentration of Zn $$= 5.0\ \text{g m}^{-3}$$, Fe $$= 0.5\ \mu\text{g mL}^{-1}$$, Mn $$= 0.05$$ ppm and Cd $$= 0.005$$ ppb. The maximum prescribed concentration of metals in drinking water in $$\text{mg dm}^{-3}$$ is Zn $$= 5.0$$, Fe $$= 0.2$$, Mn $$= 0.05$$ and Cd $$= 0.005$$. Identify the correct statement about the sample of water

In the following reaction sequence identify P, Q, R and S

The correct order of CFSE for the ions in the complexes having same ligands is

Complexes with ..... which geometry can exhibit different types of hybridization of the central metal

In the following given pairs, the one with an acidic oxide and a neutral oxide respectively is

Out of the following substances, the one that forms a white solid, has a high melting point and dissociates in water to form a basic solution is

The form in which thymine, the base present in DNA, remains at pH about 10, is

The compound not having a planar molecular configuration is

For the following molecules, the correct order of reactivity towards the $$S_N1$$ reaction is

Relationship of X and Y is

An unsaturated hydrocarbon M on oxidative ozonolysis gave a mixture of butanedioic acid and oxalic acid. The structure of the hydrocarbon M is

When 2-Methylcyclopentanone is treated with but-3-en-2-one under alkaline condition followed by heating it gives the major product X as shown in the scheme below.

This X is

Consider the chemical reaction shown 

The major product Z formed in the reaction is

Consider the set of reactions shown 

The final major product Q is

The following product P given below is obtained by Aldol condensation of

The structures of P and Q formed in the reactions shown below

An amount of 0.45 g of an organic compound X containing C, H and N on combustion produces 1.1 g of $$\text{CO}_2$$ and 0.3 g of water. Empirical formula of X is

Heptane-2,6-dione was treated with aqueous alkali and heated. The major product obtained is

The number of chiral carbons in Sphingomyelin, an important constituent of a class of lipids with the following structure, is

In the following ion the strongest hydrogen bond donor site is

The double bond equivalents for the compounds with the following molecular formulae, namely (i) $$\text{C}_{13}\text{H}_9\text{BrO}$$, (ii) $$\text{C}_3\text{H}_7\text{N}$$ and (iii) $$\text{C}_{10}\text{H}_7\text{Cl}$$, are respectively

Match the following, in which acetaldehyde is converted into different compounds listed in Column 1 using the specific reagents listed in Column 2.

The increasing order of stability of the following free radicals is

A 2 g piece of dry ice is dropped in a 5 L glass vessel containing air at 1 atm and $$25^\circ\text{C}$$ and the vessel is sealed. After some time the dry ice disappeared. (Assume that the temperature is kept constant throughout). Identify the correct statements

A thermodynamical process is represented by the cycle shown below in which 0.1 mol of a perfect gas undergoes the reversible cyclic process $$A \rightarrow B \rightarrow C \rightarrow D \rightarrow A$$. Given that $$C_{v,m} = \frac{3}{2}R$$ independent of temperature and that all symbols have their usual meaning, identify the correct statements.

Identify the correct statements for the binary solutions

The heat of combustion in $$\text{kJ mol}^{-1}$$ of ethane, propane and butane are $$-1560$$, $$-2220$$ and $$-2878$$ respectively. When 100 g of each undergoes complete combustion, which of the following statements are correct

The pH titration curve of an aqueous solution of a simple aliphatic amino acid with general formula $$\text{NH}_2\text{-CHR-COOH}$$, where R is an alkyl group, against NaOH is represented below. Identify the correct statements pertaining to it.

An aqueous solution of $$\text{CuSO}_4$$ called X is treated with certain reagents. Identify the incorrect statements

Chlorine gas can be prepared by the action of concentrated $$\text{H}_2\text{SO}_4$$ on a mixture of sodium chloride and manganese dioxide. Identify the sets of correct reactions

The 18-valence electron rule asserts that transition metal compounds are thermodynamically stable when they have a total of 18 valence electrons on the central metal, which include the metal$$'$$s d electrons and the electrons provided by the ligands attached to the metal. The 18-electron rule is obeyed by

Identify the correct statements from the following

Consider the reaction shown below,

The correct statements pertinent to the above mentioned reaction are

The tendency to undergo the Cannizzaro reaction depends upon the electrophilic nature of the carbonyl group. The four aldehydes shown below are pyrrole-2-aldehyde, chloral, p-N,N-dimethylaminobenzaldehyde and thiophene-2-aldehyde.

Identify the incorrect statements from those listed below

In the haloform reaction, the trihalogenated intermediate (−CO−CX₃) formed is then subjected to a
nucleophilic attack by the hydroxide ion (OH⁻) at the carbonyl carbon (C=O) producing a tetrahedral
intermediate, which eventually breaks down, expelling the −CX₃ group and leading to the formation of a
carboxylate anion.
Identify the correct statements regarding the iodoform reaction