Question

I am posting this question for the second time. Can anyone answer this please. I got two of them wrong.

Indicate whether each of the following solutions is acidic, basic, or neutral.

0.1 M HNO2	---Select--- acidic basic neutral
pH = 8	---Select--- acidic basic neutral
[OH1-] = 10-4M	---Select--- acidic basic neutral
[OH1-] = 10-8M	---Select--- acidic basic neutral
[H3O1+] = 10-4 M	---Select--- acidic basic neutral
[H3O1+] = 10-9 M	---Select--- acidic basic neutral

Answer 1

For, acidic solution, pH < 7

For basic solution , pH > 7

For neutral solution , pH = 7

1.

HNO₂ is acid, hence 0.1 M HNO₂ solution is acidic.

2.

For basic solution , pH > 7.

So, when pH = 8, the solution is basic.

3.

[OH^-] = 10^-4 M.

pOH = - log [OH^-] = - log (10^-4) = 4

pH + pOH = 14

Or, pH = 14 - pOH = 14 - 4 = 10.

Hence, solution is basic.

4.

[OH^-] = 10^-8 M.

pOH = - log [OH^-] = - log (10^-8) = 8

Or, pH = 14 - 8 = 6

Hence, solution is acidic.

5.

pH = - log [H₃O⁺] = - log (10^-4) = 4

Hence, solution is acidic.

6.

pH = - log [H₃O⁺] = - log(10^-9) = 9.

Hence, solution is basic.