Question

Statement 01: pure water has a pH of 7
Statement 02: the number of ${H^ + }$ ions is equal to the number of $O{H^ - }$ ions
A.Both statement 01 and statement 02 are correct and statement 02 is the correct explanation of statement 01
B.Both statement 01 and statement 02 are correct and statement 02 is the not the correct explanation of statement 01
C.Statement 01 is correct but statement 02 is not correct
D.Statement 01 is not correct but statement 02 is correct
E.Both the statement 01 and statement 02 are not correct

Answer 1

pH is a way of measuring the acidity or basicity of a given compound. It represents the amount of ${H^ + }$ ions present in the given compound. The acidic character of a compound is dependent on the concentration of the ${H^ + }$ ions present in it.

Complete step by step answer:
Higher the number of ${H^ + }$ ions present, greater is the acidic character of that compound. Mathematically, it is equivalent to the negative logarithmic value of the concentration of the ${H^ + }$ ions in a compound. It can be represented as:
$pH = - \log [{H^ + }]$
pH is measured on a scale of 1 to 14, where 1 means the most acidic while 14 means most basic. Chemically neutral substances lie on the centre of this scale, i.e. at 7. This is because the acidic character of a neutral substance is balanced by its basic character. To put it in simpler terms, let us understand another small concept: the basic character of a substance is determined by the concentration of $O{H^ - }$ ions in the compound and is put in perspective by a measure known as the pOH scale.
So, in neutral substances, the concentration of the $O{H^ - }$ and ${H^ + }$ is equivalent and they cancel each other out to give the neutral characteristic.
Now moving back to the question, we know that water is a neutral substance and hence its pH is 7. And as per the explanation above, the number of ${H^ + }$ions is equal to the number of $O{H^ - }$ions and hence they cancel out their acidic and basic properties to give water its neutral nature.
Hence, we can say that Both statement 01 and statement 02 are correct and statement 02 is the correct explanation of statement 01.

Hence, Option A is the correct option.

Note:
pH value of 7 is important because it indicates a neutral solution. All other substances are compared to this neutral point. Any solution that has a pH of less than 7 is considered acidic, and anything above a pH of 7 is basic.