The percentage of oxygen in NaOH is:

• (A)- 16%
• (B)- 4%
• (C)- 40%
• (D)- 8%

To find the percentage of oxygen in sodium hydroxide (NaOH), we first need to determine the molar mass of NaOH. Sodium (Na) has a molar mass of approximately 23 g/mol, oxygen (O) is about 16 g/mol, and hydrogen (H) is around 1 g/mol.

Calculating Molar Mass

The total molar mass of NaOH can be calculated as follows:

• Molar mass of Na = 23 g/mol
• Molar mass of O = 16 g/mol
• Molar mass of H = 1 g/mol

Adding these together gives:

Total Molar Mass of NaOH = 23 + 16 + 1 = 40 g/mol

Finding the Percentage of Oxygen

Next, we calculate the percentage of oxygen in NaOH using the formula:

Percentage of Oxygen = (Mass of Oxygen / Total Molar Mass) × 100

Substituting the values:

Percentage of Oxygen = (16 g/mol / 40 g/mol) × 100 = 40%

Final Answer

Therefore, the percentage of oxygen in NaOH is 40%. The correct option is (C).