With reference to 'acids and bases', which of the following statements is/are correct?

Question

With reference to 'acids and bases', which of the following statements is/are correct?

1. Acidic solutions have pH more than 7.

2. Basic solutions have pH less than 7.

Select the correct answer from the code given below:

1. A. Only 2
2. B. Neither 1 nor 2 (Correct answer)
3. C. Both 1 and 2
4. D. Only 1

Correct Answer

Option B — Neither 1 nor 2

Detailed Solution & Explanation

The correct answer is Neither 1 nor 2.

Key Points

• Statement 1 is incorrect. Acidic solutions have pH LESS than 7, not more.
• Statement 2 is incorrect. Basic (alkaline) solutions have pH MORE than 7, not less.
• The two statements have simply been swapped, so neither is correct — option (b).
• pH 7 is neutral, as in pure water at 25°C.

Additional Information

• pH stands for the "power of hydrogen" and is defined as pH = -log₁₀[H⁺]. It was introduced by S. P. L. Sorensen in 1909. The scale runs from 0 to 14, and each unit represents a tenfold change in hydrogen-ion concentration.
• Everyday pH values: gastric juice about 1.2-3, lemon juice about 2.2, milk about 6.8, blood about 7.4 (kept in a narrow range by buffers), baking soda solution about 9, milk of magnesia about 10.
• Applications frequently asked:
  • Tooth decay begins when the mouth's pH falls below 5.5; toothpastes are basic to neutralise the acid.
  • Plants grow best in soil of roughly neutral pH; acidic soil is treated with lime (calcium carbonate).
  • Acid rain has a pH below 5.6 and damages aquatic life when river water falls below about 5.6.
  • A bee sting is acidic (formic acid) and is treated with a mild base such as baking soda; a wasp sting is alkaline and is treated with a mild acid such as vinegar.