Which of the following factors is altered by the addition of a catalyst during a chemical reaction?
Internal energy
Activation energy
Enthalpy
Entropy
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:
$$ 2 \mathrm{CH}_4(\mathrm{~g})+4 \mathrm{O}_2(\mathrm{~g}) \rightarrow 2 \mathrm{CO}_2(\mathrm{~g})+4 \mathrm{H}_2 \mathrm{O}(\mathrm{l}) $$
$ -890.3$
$+890.3$
$+1780.6$
$ -1780.6$
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.
Reason is correct but Assertion is wrong
Both Assertion and Reason are correct and Reason is the correct explanation of Assertion
Both Assertion and Reason are correct but Reason is not the correct explanation of Assertion
Assertion is correct but Reason is wrong
Which one of the following complex-isomerism pair matches correctly?
$\left[\mathrm{CrCl}_2(\mathrm{ox})_2\right]^{3-}$ - Exhibits cis- trans isomerism and cis isomer is optically active
$\left[\mathrm{PtCl}_2\left(\mathrm{NH}_3\right)_2\right]$ - Exhibits both cis- trans and optical isomerism
$\left[\mathrm{Fe}(\mathrm{CN})_4\left(\mathrm{NH}_3\right)_2\right]^{-}$- Exhibits cis- trans isomerism and both exhibit optical isomerism
$\left[\mathrm{Cr}\left(\mathrm{C}_2 \mathrm{O}_4\right)_3\right]^{3-} \quad$ - Exhibits cis- trans isomerism but is optically inactive
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