Answer:
Vinegar.
Step-by-step explanation:
pH is the negative logarithm of the hydrogen ion concentration. pH scale has the values to measure the acidity and basicity of the substance.
Acids may be defined as the substance that pH less than seven and base the substance of pH more than seven. Since, vinegar has pH 3 it is acidic in nature and contains more H+ions then ammonia because ammonia is basic in nature.
Thus, the answer is vinegar.