Question

Which of the following has highest equivalent weight? Given: At.wt \(H=1,\ C=12,\ O=16,\ S=32,\ Na=23,\ Ca=40\)

• A. Sulphuric acid
• B. Sodium carbonate
• C. Sodium sulphate
• D. Calcium carbonate

Hint:

Compare equivalent weights by calculating \(\frac{\text{molecular weight}}{n\text{-factor}}\) for each compound.

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
To find the highest equivalent weight, we must calculate the molecular weight of each compound and divide it by its specific valence factor (\(n\)-factor).
Step 2: Detailed Explanation:

Option (A) Sulphuric acid (\(H_2SO_4\)):
Molecular weight = \(2(1) + 32 + 4(16) = 98\).
Valence factor (basicity) = 2.
Equivalent weight = \(98 / 2 = 49\).

Option (B) Sodium carbonate (\(Na_2CO_3\)):
Molecular weight = \(2(23) + 12 + 3(16) = 106\).
Valence factor (total positive charge) = 2.
Equivalent weight = \(106 / 2 = 53\).

Option (C) Sodium sulphate (\(Na_2SO_4\)):
Molecular weight = \(2(23) + 32 + 4(16) = 142\).
Valence factor (total positive charge) = 2.
Equivalent weight = \(142 / 2 = 71\).

Option (D) Calcium carbonate (\(CaCO_3\)):
Molecular weight = \(40 + 12 + 3(16) = 100\).
Valence factor (charge on Ca ion) = 2.
Equivalent weight = \(100 / 2 = 50\).

Comparing the results: 49, 53, 71, and 50.

Sodium sulphate has the highest value of 71.

Step 3: Final Answer:
The highest equivalent weight belongs to Sodium sulphate.