1
COMEDK 2026 Afternoon Shift
MCQ (Single Correct Answer)
+1
-0

The standard enthalpies of formation of $\mathrm{CH}_4(\mathrm{~g}), \mathrm{CO}_2(\mathrm{~g})$ and $\mathrm{H}_2 \mathrm{O}(\mathrm{l})$ are $-74.8 \mathrm{~kJ} \mathrm{~mol}^{-1},-393.5 \mathrm{~kJ} \mathrm{~mol}^{-1}$ and $-285.8 \mathrm{~kJ} \mathrm{~mol}^{-1}$ respectively. Then the enthalpy change for the given reaction in $\mathrm{kJ} \mathrm{mol}^{-1}$ will be:

$$ 2 \mathrm{CH}_4(\mathrm{~g})+4 \mathrm{O}_2(\mathrm{~g}) \rightarrow 2 \mathrm{CO}_2(\mathrm{~g})+4 \mathrm{H}_2 \mathrm{O}(\mathrm{l}) $$

A

$ -890.3$

B

$+890.3$

C

$+1780.6$

D

$ -1780.6$

2
COMEDK 2026 Afternoon Shift
MCQ (Single Correct Answer)
+1
-0

With reference to the two statements Assertion and Reason, choose the correct option.

Assertion: The order of reactivity towards $\mathrm{S}_{\mathrm{N}} 1$ reaction is: $\mathrm{C}_6 \mathrm{H}_5-\mathrm{CH}_2 \mathrm{Br}>\left(\mathrm{CH}_3\right)_3-\mathrm{C}-\mathrm{Br}>\left(\mathrm{CH}_3\right)_2-\mathrm{CH}-\mathrm{Br}$.

Reason: Among the given 3 compounds, the Benzyl carbocation formed is the most stable while Isopropyl carbocation is the least stable one.

A

Reason is correct but Assertion is wrong

B

Both Assertion and Reason are correct and Reason is the correct explanation of Assertion

C

Both Assertion and Reason are correct but Reason is not the correct explanation of Assertion

D

Assertion is correct but Reason is wrong

3
COMEDK 2026 Afternoon Shift
MCQ (Single Correct Answer)
+1
-0

Which one of the following complex-isomerism pair matches correctly?

A

$\left[\mathrm{CrCl}_2(\mathrm{ox})_2\right]^{3-}$ - Exhibits cis- trans isomerism and cis isomer is optically active

B

$\left[\mathrm{PtCl}_2\left(\mathrm{NH}_3\right)_2\right]$ - Exhibits both cis- trans and optical isomerism

C

$\left[\mathrm{Fe}(\mathrm{CN})_4\left(\mathrm{NH}_3\right)_2\right]^{-}$- Exhibits cis- trans isomerism and both exhibit optical isomerism

D

$\left[\mathrm{Cr}\left(\mathrm{C}_2 \mathrm{O}_4\right)_3\right]^{3-} \quad$ - Exhibits cis- trans isomerism but is optically inactive

4
COMEDK 2026 Afternoon Shift
MCQ (Single Correct Answer)
+1
-0

Identify the correct statement.

A

The " D " in $\mathrm{D}(+)$-glucose represents the dextrorotatory nature of Glucose and ( + ) stands for its configuration

B

During denaturation of Proteins its 3- dimensional structure is destroyed because the primary, secondary and tertiary structures get destroyed due to rise in temperature

C

Except Glycine and Tryptophan all the other naturally occurring Amino acids are optically active

D

Glucose gets oxidised to Gluconic acid with $\mathrm{Br}_2(\mathrm{aq})$ which indicates that the carbonyl group in it is an Aldehydic group