1
COMEDK 2025 Afternoon Shift
MCQ (Single Correct Answer)
+1
-0
The hydrogenation of Ethyne is carried out at 600 K . The same reaction when carried out in presence of a catalyst maintaining the same rate constant, the temperature required is only 400 K . If the catalyst lowers the Activation energy of the reaction by $20 \mathrm{~kJ} / \mathrm{mol}$, what is the value of $\mathrm{E}_{\mathrm{a}}$ ?
A
$60 \mathrm{~kJ} / \mathrm{mol}$
B
$100 \mathrm{~kJ} / \mathrm{mol}$
C
$50 \mathrm{~kJ} / \mathrm{mol}$
D
$80 \mathrm{~kJ} / \mathrm{mol}$
2
COMEDK 2025 Afternoon Shift
MCQ (Single Correct Answer)
+1
-0

Complete the following 2 reactions A \& B by choosing appropriate reactants $[\mathrm{X}] \&[\mathrm{Y}]$.

COMEDK 2025 Afternoon Shift Chemistry - Alcohol, Phenols and Ethers Question 5 English

A
$[\mathrm{X}]=\mathrm{C}_6 \mathrm{H}_5 \mathrm{CHO}\qquad$ $[\mathrm{Y}]=\mathrm{CH}_3-\mathrm{CO}-\mathrm{CH}_3$
B
$[\mathrm{X}]=\mathrm{C}_6 \mathrm{H}_5 \mathrm{Br}\qquad$ $[\mathrm{Y}]=\mathrm{CH}_3 \mathrm{CH}_2-\mathrm{N}-\left(\mathrm{CH}_3\right)_2$
C
$[\mathrm{X}]=\mathrm{C}_6 \mathrm{H}_5 \mathrm{OH}\qquad$ $[\mathrm{Y}]=\mathrm{C}_6 \mathrm{H}_5-\mathrm{N}-\left(\mathrm{CH}_3\right)_2$
D
$[\mathrm{X}]=\mathrm{C}_6 \mathrm{H}_5 \mathrm{NH}_2\qquad$ $[\mathrm{Y}]=\mathrm{C}_6 \mathrm{H}_5 \mathrm{OH}$
3
COMEDK 2025 Afternoon Shift
MCQ (Single Correct Answer)
+1
-0
The time needed for completion of $80 \%$ is $y$ times the half-life period of a first order reaction. What is the value of $y$ ?
A
0.648
B
3.46
C
2.32
D
0.322
4
COMEDK 2025 Afternoon Shift
MCQ (Single Correct Answer)
+1
-0
A current of 1.5 A is passed for 2 hours through an aqueous solution of $\mathrm{PdX} \mathrm{n}_{\mathrm{n}}$ where X is a monovalent anion. During the electrolysis process 2.977 g of Palladium metal gets deposited at the cathode. Calculate the charge on Pd ions. (Atomic mass of $\mathrm{Pd}=106.4 \mathrm{~g} / \mathrm{mol}$ ).
A
$\mathrm{n}=4$
B
$\mathrm{n}=6$
C
$\mathrm{n}=3$
D
$\mathrm{n}=2$
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