Question

What is the pH value of drinking water?
a.) < 7
b.) > 7
c.) equal to 7
d.) none

Answer 1

Hint: The value for safe drinking water is not a single value. But it lies in the range. The pH range for safe drinking lies in 6.5 to 8.5 range. More basic nature of water is not as harmful as the acidic one is.

Complete step by step answer :
First let us understand what is pH and how its change affects the quality of drinking water.
The pH may be defined as the scale used for measurement of electrically charged particles. It defines how acidic or basic is the solution. The pH scale has a range of 0 to 14. The point 7 is considered neutral here.
If the value of water comes out to be less than 7; then it is acidic in nature and if the value comes out to be more than the water is basic in nature.
Thus, the pure water has a pH value of 7. It is neutral in nature.
According to the standard measurements, the pH value for safe drinking water lies in the range of 6.5 to 8.5.
So, if we see our options; the option a.) says that the value is less than 7 which is right if we think about value 6.5. But the pH value is less than 6.5 i.e. the numbers 3, 4 and 5 also come under less than 7. But these can not be the accurate pH values for safe drinking water.
Thus, option a.) can not be considered the correct answer.
Now, the option b.) says that pH value should be greater than 7. Same is the case here, if we see the values 8.5; then it seems to be the correct answer. But again, the values 9, 10 and 11 etc. also come under greater than 7.
So, even the option b.) is not the correct answer.
Now, coming to option c.). According to this, the pH should be equal to 7. It is true that pure water contains this pH which is considered neutral. This value 7 also is in the range of 6.5 to 8.5 but this neutral pH will exist all over the world is not possible. It is an exact value which is not possible always.
So, even the option c.) is not the correct answer.
The pH value lies in the range of 6.5 to 8.5. It can be any number in this range. There can not be a specific number.

So, the option d.) which is none of the above is the correct answer.

Note :
The water is acid rain is acidic in nature and is not safe for drinking or for plants. It has a pH value of 5 to 5.5. The water in bottles which are labelled as alkaline or basic has a Ph value of 8 to 9.