Which of the following has a pH value of 7?
Pure Water
The correct answer is Pure Water.
The pH scale measures the acidity or alkalinity of a solution. It ranges from 0 to 14, with 7 representing a neutral solution. A pH less than 7 indicates acidity, while a pH greater than 7 indicates alkalinity. Pure water, at 25°C, has a pH of 7 because the concentration of hydrogen ions (\(H^+\)) and hydroxide ions (\(OH^-\)) are equal. This balance results in a neutral solution. In contrast, acids like sulfuric acid (\(H_2SO_4\)) and hydrochloric acid (HCl) have pH values significantly less than 7 due to their high concentration of \(H^+\) ions. Conversely, bases like sodium carbonate have pH values greater than 7. The pH of a substance depends on the concentration of \(H^+\) and \(OH^-\) ions present in the solution. A neutral solution like pure water maintains an equal concentration of both ions. Understanding the dissociation of water into these ions is crucial in comprehending the neutrality of pure water at its standard pH of 7. Deviation from this pH can occur due to the presence of impurities and changes in temperature.
Important Questions from Acids, Bases & Salts
When a large amount of carbon dioxide dissolves in a water body, the water becomes acidic because of the formation of which of the following acids?
Which one of the following oxides is a neutral oxide?
- Which of the following solutions is slightly acidic due to hydrolysis?
- Which of the following foods would you advise to neutralise excess stomach acids?
- What is the primary contributor to the sour taste in foods like lemons, vinegar and yoghurt?
