1.

pH of 10^(-8) M HNO_(3) is (nearly)

Answer»

7
6.96
7.2
6

Solution :`{:(,HNO_(3),RARR,H^(+),+,NO_(3)^(-)),("Conc. before ionisation",10^(-8)M,,0,,0),("Conc. after ionisation",0,,10^(-8),,10^(-8)):}`
`:. [H^(+)] = 10^(-8) m` but pH = 8 is not POSSIBLE because it is acid. Now `[H^(+)] = 10^(-7) M` are already present in solution and SINCE `10^(-8) lt 10^(-7)` and thus, it should not be NEGLECTED.
`:. [H^(+)] = 10^(-8) + 10^(-7) = 10^(-7)(1.1) M`
`= 1.1 xx 10^(-7)M`
`:. pH = 6.9586`.


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