Out of 1000 molecules of acetic acid are_ dissociated into ions.

Explanation

Acetic acid (CH3COOH) is a weak acid, meaning it does not fully ionize in solution. Typically, only about 1-2% of acetic acid molecules dissociate into ions in water. Therefore, out of 1000 molecules, approximately 13 (1.3%) dissociate, making option A correct. Option B (15) and Option C (17) indicate a higher dissociation rate than expected for a weak acid. Option D (11) suggests a lower dissociation rate than the typical range. Hence, option A is the most accurate reflection of acetic acid's dissociation behavior.