Question

State True (T) or False (F) and select the correct option:

• [(a)] Alcohols can react both as electrophile and nucleophile.

• [(b)] Ethanol is stronger than methanol with respect to acidic character.

• [(c)] The C--O bond length in phenol is slightly less than that in methanol.

• [(d)] The \(\angle C-O-C\) bond angle in methoxyethane is slightly smaller than normal tetrahedral angle.

• A. (a)-F, (b)-T, (c)-F, (d)-T
• B. (a)-T, (b)-F, (c)-T, (d)-F
• C. (a)-T, (b)-F, (c)-F, (d)-T
• D. (a)-F, (b)-T, (c)-T, (d)-F

Hint:

• Methanol is more acidic than ethanol.

• Phenol has shorter C--O bond due to resonance.

• Alcohols may behave as both nucleophiles and electrophiles.

• In ethers, \(\angle C-O-C\) is generally greater than \(109.5^\circ\).

Answer 1

The Correct Option is B

Step 1: Test statement (a).
The oxygen of an alcohol carries lone pairs, so it can donate them and act as a nucleophile. When protonated, the carbon end can be attacked, so it can also behave as an electrophile. Statement (a) is True.

Step 2: Test statement (b).
Ethyl group pushes electrons more strongly than methyl (greater $+I$ effect). This makes the $O-H$ bond hold its electrons tighter, so ethanol is a weaker acid than methanol, not stronger. Statement (b) is False.

Step 3: Test statement (c).
In phenol the oxygen lone pair goes into the ring, giving the $C-O$ bond partial double bond character. This shortens it compared to the plain single $C-O$ bond in methanol. Statement (c) is True.

Step 4: Test statement (d).
In methoxymethane type ethers, lone pair repulsions on oxygen push the bonds slightly, but the $C-O-C$ angle is actually a little larger than the tetrahedral angle, not smaller. Statement (d) is False.

Step 5: Line up the results.
We get (a) True, (b) False, (c) True, (d) False.

Step 6: Pick the matching option.
This matches the option (a)-T, (b)-F, (c)-T, (d)-F.
\[ \boxed{(a)\text{-}T,\ (b)\text{-}F,\ (c)\text{-}T,\ (d)\text{-}F} \]