`Ph-N=C=Ounderset((ii)H_2O)overset((i)CH_3MgBr)toPoverset(LiAH_4)toQ`
P and Q is

Options

A. P is `Ph-NH-underset(O)underset(||)C-CH_3` and Q is `Ph-NH-CH_2-CH_3`
B. P is `Ph-NH-CH_3` and Q is `NH_3`
C. P is `PhN=oversetoverset(CH_3)(|)C-OH` and Q is `Ph-NH-CH_3`
D. P is `Ph-NH-undersetunderset(OH)(|)CH-CH_3` and
Q is `Ph-NH-undersetunderset(CH_3)(|)CH-CH_3`

Explanation

To solve the problem step by step, we will analyze the reactions involving phenyl isocyanate (Ph-N=C=O) and identify the products P and Q.

### Step 1: Identify the starting compound
The starting compound is phenyl isocyanate, which has the structure:
\[ \text{Ph-N=C=O} \]

### Step 2: Reaction with CH3MgBr (Grignard reagent)
When phenyl isocyanate reacts with methylmagnesium bromide (CH3MgBr), the nucleophilic carbon from the Grignard reagent attacks the electrophilic carbon of the isocyanate. This results in the formation of a compound that contains a carbonyl group and an amine group.

The reaction can be represented as:
\[ \text{Ph-N=C=O} + \text{CH}_3\text{MgBr} \rightarrow \text{Ph-NH-C(=O)-CH}_3 \]

This product is a secondary amide, which we will denote as P:
\[ P = \text{Ph-NH-C(=O)-CH}_3 \]

### Step 3: Reaction with H2O
The next step involves the addition of water (H2O), which hydrolyzes the intermediate formed in the previous step. This does not change the structure significantly, and we still have:
\[ P = \text{Ph-NH-C(=O)-CH}_3 \]

### Step 4: Reaction with Lithium Aluminium Hydride (LiAlH4)
Now, we treat the secondary amide P with lithium aluminium hydride (LiAlH4), which is a strong reducing agent. This reduces the amide to a secondary amine.

The reaction can be represented as:
\[ \text{Ph-NH-C(=O)-CH}_3 + \text{LiAlH}_4 \rightarrow \text{Ph-NH-CH}_3 + \text{LiAlO}_2 + \text{H}_2\text{O} \]

The product Q is therefore:
\[ Q = \text{Ph-NH-CH}_3 \]

### Final Products
- **P**: Ph-NH-C(=O)-CH3 (secondary amide)
- **Q**: Ph-NH-CH3 (secondary amine)

### Summary of Products
- P is a secondary amide: **Ph-NH-C(=O)-CH3**
- Q is a secondary amine: **Ph-NH-CH3**