1
COMEDK 2025 Morning Shift
MCQ (Single Correct Answer)
+1
-0
Two volatile liquids X and Y form an ideal solution at 298 K and have vapour pressures equal to 100 mm and 200 mm of Hg respectively in their pure state. The mole fraction of X in the solution is 0.4 and the mole fraction of Y in the vapour phase is $a / 20$. Calculate the value of a.
A
25
B
15
C
10
D
5
2
COMEDK 2025 Morning Shift
MCQ (Single Correct Answer)
+1
-0
0.4 g of Propane burns completely at 300 K in a bomb calorimeter. The temperature of the calorimeter and surrounding water rises by $0.4^0 \mathrm{C}$. If the heat capacity of the calorimeter and contents is $24 \mathrm{~kJ} \mathrm{~K}^{-1}$ what is the Enthalpy for the reaction? (Assume that propane gas shows ideal behaviour).
A
$-$1006.9 kJ
B
$-$1063.5 kJ
C
$-$2084.6 kJ
D
$-$1902.8 kJ
3
COMEDK 2025 Morning Shift
MCQ (Single Correct Answer)
+1
-0

Match the metals in Column II with their characteristic properties given in Column I.

Properties Metals
A. Lanthanoid with low value of $3^{\text {rd }}$ ionisation enthalpy. P V
B. f-Block element with electronic configuration $[R n] 6 d^2 7 s^2$ Q Gd
C. 3 d -series metal whose $\mathrm{M}^{3+}{ }_{(\mathrm{aq})}$ is colourless. R Th
D. 3d-series metal with highest $\Delta \mathrm{H}_{\text {(atomisation) }}$ S Sc

A
$\mathrm{A}=\mathrm{Q} \quad \mathrm{B}=\mathrm{R} \quad \mathrm{C}=\mathrm{S} \quad \mathrm{D}=\mathrm{P}$
B
$\mathrm{A}=\mathrm{R} \quad \mathrm{B}=\mathrm{Q} \quad \mathrm{C}=\mathrm{S} \quad \mathrm{D}=\mathrm{P}$
C
$\mathrm{A}=\mathrm{R} \quad \mathrm{B}=\mathrm{Q} \quad \mathrm{C}=\mathrm{P} \quad \mathrm{D}=\mathrm{S}$
D
$\mathrm{A}=\mathrm{S} \quad \mathrm{B}=\mathrm{R} \quad \mathrm{C}=\mathrm{Q} \quad \mathrm{D}=\mathrm{P}$
4
COMEDK 2025 Morning Shift
MCQ (Single Correct Answer)
+1
-0

Convert Benzene $\rightarrow 3$-Bromophenol by choosing appropriate reagents [(i) to (v)] in the correct sequence.

(i) $\mathrm{NaNO}_2 / \mathrm{HCl}\left(0^{\circ} \mathrm{C}\right)$

(ii) Conc. $\mathrm{HNO}_3 / \mathrm{H}_2 \mathrm{SO}_4$

(iii) $\mathrm{H}_2 \mathrm{O} / 283 \mathrm{~K}$

(iv) $\mathrm{Fe} / \mathrm{HCl}$

(v) $\mathrm{Br} 2 / \mathrm{Fe}$

A
v, ii, iii, i, iv
B
ii, v, iv, i, iii
C
iii, iv, v, ii, i
D
v, ii, i, iv, iii
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