Question

In the following reaction sequence, the major product P is formed.

Glycerol reacts completely with excess P in the presence of an acid catalyst to form Q. Reaction of Q with excess NaOH followed by the treatment with CaCl₂ yields Ca-soap R, quantitatively. Starting with one mole of Q, the amount of R produced in gram is ______.
[Given, atomic weight: H = 1, C = 12, N = 14, O = 16, Na = 23, Cl = 35, Ca = 40]

Answer 1

Correct Answer: 909

Step 1: Understanding the Reaction Sequence 

• The reaction sequence produces a fatty acid (Q), which undergoes saponification with NaOH.
• The final step involves the reaction of Q with CaCl₂, forming a calcium salt of the fatty acid (R).

Step 2: Identifying the Molecular Formula of R

The structure of R is a calcium salt of a long-chain fatty acid, given by:

$$ (C_{17}H_{35}COO)_2Ca $$

Step 3: Calculating the Molar Mass of R

• Carbon (C): \( 36 \times 12 = 432 \)
• Hydrogen (H): \( 70 \times 1 = 70 \)
• Oxygen (O): \( 4 \times 16 = 64 \)
• Calcium (Ca): \( 1 \times 40 = 40 \)

Step 4: Total Molar Mass of R

$$ 432 + 70 + 64 + 40 = 606 \text{ g/mol} $$

Step 5: Scaling for One Mole of Q

Since 1 mole of Q forms 1 mole of R, the final mass of R produced is:

$$ \text{Mass of R} = 1.5 \times 606 = 909 \text{ g} $$