Multiple Choice QuestionsWhich one of the following is the correct order of increasing basic strength of nitrogen compounds in aqueous solution?
NH3 < C2H5NH2 < C6H5NH2 < (C2H5)2NH < C6H5CH2NH2
C6H5NH2 < NH3 < C6H5CH2NH2 < C2H5NH2 < (C2H5)2NH
(C2H5)2NH < C6H5CH2NH2 < NH3 < C2H5NH2 < C6H5NH2
C6H5CH2NH2 < C2H5NH2 < NH3 < C6H5NH2 < (C2H5)2NH
B.
C6H5NH2 < NH3 < C6H5CH2NH2 < C2H5NH2 < (C2H5)2NH
Basic character depends upon the availability of lone pair of N atom for donation. Presence of electron donating group like -R, increases the electron density at N-atom and thus makes its lone pair more available for donation.
Aromatic amines are generally less basic because of the involvement of lone pair of nitrogen in delocalisation. Thus, the correct order of increasing basic strength is-
C6H5NH2 < NH3 < C6H5CH2NH2 < C2H5NH2 < (C2H5)2NH
The gas emitted by supersonic jet planes that slowly depletes the concentration of ozone layer is
CO
NO
SO2
O2
Among the following compounds, the one that gets hydrolysed to form metallic hydroxide, hydrogen peroxide and oxygen is
Na2O
Na2O2
Li2O
KO2
Freezing point of an aqueous solution is -0.186°C. If the values of Kb and Kf of water are respectively 0.52 K kg mol-1 and 1.86 K kg mol-1 then the elevation of boiling point of the solution in K is
0.052
0.52
1.04
1.34
A weak electrolyte having the limiting equivalent conductance of 400 S cm2 g equiv-1 at 298 K is 2% ionized in its 0.1 N solution. The resistance of this solution (in ohm) in an electrolytic cell of cell constant 0.4 cm-1 at this temperature is
200
300
400
500
Given that the standard reduction potentials for M+ / M and N+ / N electrodes at 298 K are 0.52 V and 0.25 V respectively. Which of the following is correct in respect of the following electrochemical cell?
M | M+ || N+ | N
The overall cell reaction is a spontaneous reaction
The standard EMF of the cell is -0.27 V
The standard EMF of the cell is 0.77 V
The standard EMF of the cell is -0.77 V
The rate constant of a first order reaction is doubled when the temperature is increased from 20°C to 25°C. How many times the rate constant will increase if the temperature is raised from 20°C to 40°C?
4
8
16
32
In the following reaction, the initial concentrations of the reactant and initial rates at 298 K are given
2A → C + D
| [A]0 mol L-1 | Initial rate in mol L-1s-1 |
| 0.01 | 5.0 × 10-5 |
| 0.02 | 2.0 × 10-4 |
The value of rate constant of this reaction at 298 K is
0.01 s-1
5 × 10-3 mol L-1 s-1
2.0 × 10-2 mol-1 Ls-1
5 × 10-1 mol-1 Ls-1
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