1
COMEDK 2025 Afternoon Shift
MCQ (Single Correct Answer)
+1
-0
Which one of the following molecules attains greater stability on formation of its diatomic monovalent anion?
A
$\mathrm{C}_2$
B
$\mathrm{O}_2$
C
$\mathrm{N}_2$
D
$\mathrm{F_2}$
2
COMEDK 2025 Afternoon Shift
MCQ (Single Correct Answer)
+1
-0

The Standard Reduction potential at $25^{\circ} \mathrm{C}$ for $\left(\mathrm{MnO}_4\right)^{-1} / \mathrm{H}^{+}$is +1.49 V . The $\mathrm{E}^0$ values for four Metal ions :

(a). $\mathrm{Co}^{3+} / \mathrm{Co}^{2+}$

(b). $\mathrm{Cr}^{3+} / \mathrm{Cr}$

(c). $\mathrm{Au}^{3+} / \mathrm{Au}$ and

(d). $\mathrm{Ag}^{+} / \mathrm{Ag}$

are $+1.81 \mathrm{~V},-0.74 \mathrm{~V},+1.50 \mathrm{~V}$ and +0.8 V respectively. Identify two of them which cannot be oxidised by $\left(\mathrm{MnO}_4\right)^{-1} / \mathrm{H}^{+}$

A
a & d
B
a & c
C
b & d
D
b & c
3
COMEDK 2025 Afternoon Shift
MCQ (Single Correct Answer)
+1
-0
The best method for the separation of $o$-nitrophenol and $p$-nitrophenol from their mixture is :
A
Crystallisation
B
Steam distillation
C
Sublimation
D
Simple distillation
4
COMEDK 2025 Afternoon Shift
MCQ (Single Correct Answer)
+1
-0
For the reaction $\mathrm{A}_2+\mathrm{B}_2 \cdots \cdots>2 \mathrm{AB}, \Delta \mathrm{H}_{\mathrm{f}}=-400 \mathrm{~kJ} / \mathrm{mol}$. The bond dissociation enthalpies of $\mathrm{A}_2$, $\mathrm{B}_2$ and AB are in the ratio $1: 0.75: 1$. What is the bond dissociation enthalpy of $\mathrm{B}_2$ in $\mathrm{kJ} / \mathrm{mol}$ ?
A
1600
B
2400
C
3200
D
800
EXAM MAP