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JEE Advance - Chemistry (2001)

1
The vapour pressure of the two miscible liquids (A) and (B) are 300 and 500 mm of Hg respectively. In a flask 10 moles of (A) is mixed with 12 moles of (B). However, as soon as (B) is added, (A) starts polymerizing into a completely insoluble solid. The polymerization follows first-order kinetics. After 100 minutes, 0.525 mole of a solute is dissolved which arrests the polymerization completely. The final vapour pressure of the solution is 400 mm of Hg. Estimate the rate of constant of the polymerization reaction. Assume negligible volume change on mixing and polymerization and ideal behaviour for the final solution.
Answer
(C)
1. 004 x 10^-4 min^-1
1
An aqueous solution of 6.3 g oxalic acid dihydrate is made up to 250ml. the volume of 0.1N NaOH required to completely neutralize 10ml of this solution is :
Answer
(A)
40ml
2
The rate of a first order reaction is 0.04 mol litre-1 s-1 at 10 minutes and 0.03 mol litre-1 s-1 at 20 minutes after initiation. Find the half-life of the reaction.
Answer
(B)
24.27 min
2
The reaction, $$3Cl{O^ - }(aq)$$$$ \to ClO_3^ - (aq) + 2C{l^ - }(aq)$$ is an example of :
Answer
(C)
Disproportionate reaction
3
The standard potential of the following cell is 0.23V at 15oC and 0.21 V at 35oC.
Pt | H2 (g) | HCl (aq) | AgCl (s) | Ag (s)
(i) Write the cell reaction.
(ii) Calculate $$\Delta H^o$$ and $$\Delta S^o$$m for the cell reaction by assuming that these quantities remain unchanged in the range 15oC to 35oC.
(iii) Calculate the solubility of AgCl in water at 25oC
Given : The standard reduction potential of the Ag+ (aq) / Ag (s) couple is 0.80 V at 25oC
Answer
(A)
$$\Delta H^o = -49.9 kJ/mol, \Delta S^o = -96.5 J/mol \cdot K$$, Solubility = $$1.21 \times 10^{-5} mol/L$$
3
In the standardization of Na2S2O3 using K2Cr2O7 by iodometry, the equivalent weight of K2Cr2O7 is:
Answer
(B)
(molecular weight)/6
4
Hydrogen peroxide solution (20 ml) reacts quantitatively with a solution of KMnO4 solution is just decolourised by 10 ml of MnSO4 in neutral medium simultaneously forming a dark brown precipitate of hydrated MnO2. The brown precipitated is dissolved in 10 ml of 0.2 M sodium oxalate under boiling condition in the presence of dilute H2SO4. Write the balanced equations involved in the reactions and calculate the molarity of H2O2.
Answer
(B)
0.1 M
4
The wavelength associated with a golf ball weighing 200 g and moving at speed of 5 m/h is of the order
Answer
(C)
10-30 m
5
The quantum numbers +1/2 and -1/2 for the electron spin represent
Answer
(D)
two quantum mechanical spin states which have no classical analogue
6
The common features among the species CN-, CO and NO+ are :
Answer
(A)
bond order three and isoelectronic
7
The set representing the correct order of first ionization potential is
Answer
(B)
Be > Mg > Ca