Identify the products in the following disproportional reaction and also mention rate determining step.
`2H-overset(D)overset(|)(C)=O + overset(@)(O)H to underset("(P)")("Acid salt")+underset("(Q)")("Alcohol")`

Answer

To solve the question regarding the disproportionation reaction of deuterated formaldehyde, we will follow these steps:

### Step 1: Identify the Reactants
The reactants given are two equivalents of deuterated formaldehyde (HCD=O) and hydroxide ion (OH⁻).

### Step 2: Understand the Reaction Mechanism
In a basic medium, the hydroxide ion (OH⁻) acts as a nucleophile and attacks the electrophilic carbon of the carbonyl group in formaldehyde. The presence of deuterium (D) makes the reaction interesting because deuterium is more reactive than hydrogen.

### Step 3: First Step of the Reaction
The first equivalent of deuterated formaldehyde reacts with hydroxide ion (OH⁻). The nucleophilic attack leads to the formation of a tetrahedral intermediate:
\[ \text{HCD=O} + \text{OH}^- \rightarrow \text{HCD(OH)O}^- \]

### Step 4: Rate Determining Step
The rate determining step (RDS) occurs when the nucleophile (OH⁻) attacks the carbonyl carbon. This step is slow because it involves breaking the C=O bond and forming a new C-O bond. Thus, the RDS is:
\[ \text{HCD=O} + \text{OH}^- \text{ (slow)} \]

### Step 5: Second Step of the Reaction
The tetrahedral intermediate can then react with another equivalent of formaldehyde. The deuterium (D), being more reactive, will facilitate the reaction:
\[ \text{HCD(OH)O}^- + \text{HCHO} \rightarrow \text{DCOO}^- + \text{CH}_2\text{D-OH} \]

### Step 6: Identify the Products
The products formed are:
- **(P)**: Acid salt, which is deuterated carboxylate (DCOO⁻).
- **(Q)**: Alcohol, which is deuterated methanol (CH₂D-OH).

### Final Products
Thus, the final products of the reaction are:
- **(P)**: DCOO⁻ (Acid salt)
- **(Q)**: CH₂D-OH (Alcohol)

### Summary of the Solution
- Products identified:
- (P) Acid salt: DCOO⁻
- (Q) Alcohol: CH₂D-OH
- Rate determining step: Nucleophilic attack of OH⁻ on the carbonyl carbon of deuterated formaldehyde.