To determine which substance is likely to be Nitric (V) acid and which one is likely to be toothpaste, we need to understand the typical pH values of these substances:
(i) Nitric (V) acid:
Nitric (V) acid, also known as nitric acid, is a strong acid. Strong acids typically have very low pH values, usually below 3. Among the given options, we look for the lowest pH value.
- pH of Substance P: 9.0
- pH of Substance Q: 2.2
- pH of Substance R: 13.5
- pH of Substance S: 4.8
The lowest pH value here is 2.2, corresponding to Substance Q. Thus, the substance most likely to be Nitric (V) acid is:
Answer for (i): Q
(ii) Toothpaste:
Toothpaste is generally basic because it is formulated to neutralize the acids in the mouth. Toothpastes usually have pH values around 8-9. Among the provided substances, we will choose the one with a pH value that falls within this range.
- pH of Substance P: 9.0
- pH of Substance Q: 2.2
- pH of Substance R: 13.5
- pH of Substance S: 4.8
The pH of 9.0 matches the typical pH range of toothpaste. Therefore, the substance most likely to be toothpaste is:
Answer for (ii): P
