Answer:
Hydrogen ion.
Explanation:
Hydrogen ion is present in the acids which indicates if they are safe for eating or not. The weak acid is present in citrus so it is safe to eat. Weak acid means the concentration of hydrogen ion is lower. If this concentration exceeds so the food is not safe to eat or drink. The pH of acid more than 5 is good to eat but below 5 can adversely affect our body if we consume it.
