8. Based on what we have learned about the pH scale, if I told you that at a pH

Question

8. Based on what we have learned about the pH scale, if I told you that at a pH of 7 the (H'] was I 10 then a. at a pH of 8 there would be 1 x 10*H. b. at a pH of 5 there would be 1 x 10 H c. at a pH of 8 there would be 1 x 10 H. d. at a pH of 5 there would be 1 x 108 H OH 7 0.000000 11. In the presence of the buffer H2CO3 ??HCO' + H, as hydrogen ions are added to the solution from an outside source a. more HCOs forms to buffer the added hydrogen ions. b. more H CO, forms to buffer the added hydrogen ions. c. the equation is driven to the right. d. Nothing happens as this buffer cannot affect [H'].

Explanation / Answer

Ans8:

(b) at a pH of 5, there would be 1×10^-5 H+.

At pH 7, [H+]=1×10^-7

As pH increases [H+] decreases by a factor of 10, and as pH decreases [H+] increases by the same factor.

Now, at pH 8, H+ concentration = (1×10^-7)/10

=1×10^-8

At pH 5, there will be an increase by 10×10=100 fold (as from pH 7 to 5, there will be 2 times change)

Thus [H+]=(1×10^-7)×100

=1×10^-5

Thus, Correct choice is B.

Ans 11: (b) More H2CO3 forms.

H+ ions will react with HCO3- to form H2CO3.

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