Question

Which of the following substance have maximum value of pH? (a) Lemon (b) Rain water (c) Sea water (d) Apple

Answer 1

Lemon has more on value

Answer 2

(a) Lemon - 2

(b) Rain water - 7

(c) Sea water - 8

(d) Apple - 4

Explanation:

We know that,

• Acids have pH less than 7
• Bases have pH greater than 7
• A neutral solution has pH equal to 7.

We also know that, from the question,

• Lemon and Apple comes under Acid.
• Sea water comes under Base.
• Rain water comes under neutral.

More about this Topic :

What is pH ?

The pH is the negative logarithm of the hydrogen ion concentration.

i. e. $pH = -log_{10}[H^+]$

Why is the pH of rain water neutral ?

The pH of rain water is approximately 7, which means that it is neutral and also represents it's high purity. If the atmospheric air is polluted with oxide gases of sulphur and nitrogen, they get dissolved in the rain water and make it's pH less than 7. Thus, If the pH of rain water is less than 7, then it is called acid rain.

Common acids and their pH values :

• Vinegar - 3
• Oranges - 3.5
• Fresh milk - 5
• Human saliva - 6 - 8

Common Bases and their pH values :

• Egg white - 8
• Baking soda - 9
• Coffee - 5.6
• Blood plasma - 7.4