Question

Which of the following accounts for the observation that the pH of pure water at 37°C is 6.8 ? (A) At 37°C water is naturally acidic. (B) At 37°C the autoionization constant for water, K., is larger than it is at 25°C. (C) At 37°C water has a lower density than it does at 25°C; therefore, [H] is greater. (D) At 37°C water ionizes to a lesser extent than it does at 25°C.

Answer 1

b

Step-by-step explanation:

A. it's not acidic since concentrations are still [H+]=[OH-]

B. if autoionization constant K gets larger, it means that the product [H+].[OH-] is larger, this is, [H+] and [OH-] have larger values than 10^-7. This means pH will be lower than 7

C. it does have a lower density, but it has nothing to do with [H+]

D. the observation showed that pH = 6.8, then [H+] must be 10^-6.8, this means we have more H+ now, then water must be ionizing to a greater extent.