Q. 55.0( 6 Votes )
A little distille
A. pH value of distilled water is 7.
The pH scale is the method to express the acidity/alkalinity of a solution. It is based on the amount of H+ ions present in a given solution.
Lesser the value of pH, more will be the acidity. For a neutral solution the pH value is 7. Distilled water is neutral in nature because equal number of H+ and OH- are present in it. Thus distilled water has a pH value of 7.
B. The pH value will change when caustic soda or vinegar is added to the distilled water as follows:
a. pH value will increase and become much greater than 7 on adding caustic soda to water.
Caustic soda is general name for NaOH which is a strong base. So when we add caustic soda to water, it will make the water basic in nature. A basic solution has a pH greater than 7. So we can say that adding caustic soda will make the pH of water greater than 7.
b. pH value will decrease and become slightly less than 7 on adding vinegar to water.
Vinegar contains acetic acid which is a weak acid. So when we add vinegar to water, it will make the water acidic in nature. An acidic solution has a pH less than 7. So we can say that adding vinegar will make the pH of water less than 7.
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