What is the mass percent of chlorine in hydrochloric acid (HCl)?

• A. 76.5%
• B. 97.2%
• C. 50.0%
• D. 36.5%

Answer: (A)

Verified step by step guidance

1. Identify the chemical formula of hydrochloric acid, which is HCl, consisting of one hydrogen (H) atom and one chlorine (Cl) atom.
2. Find the atomic masses of hydrogen and chlorine from the periodic table: approximately 1.0 g/mol for H and 35.5 g/mol for Cl.
3. Calculate the molar mass of HCl by adding the atomic masses: \(\text{Molar mass of HCl} = 1.0 + 35.5\) g/mol.
4. Determine the mass percent of chlorine in HCl using the formula: \(\text{Mass \% Cl} = \left( \frac{\text{Mass of Cl}}{\text{Molar mass of HCl}} \right) \times 100\%\).
5. Substitute the values into the formula and simplify the expression to find the mass percent of chlorine in hydrochloric acid.