A solution contains 0.1M H_2S and 0.3M HCI. If K_a and K_(a2) for H_2 S are 1 xx 10^(-7) and 1.3 xx 10^(-13) respectively, calculate concentration of HS^- and S^- in the mixture.

A solution contains 0.1M H_2S and 0.3M HCI. If K_a and K_(a2) for H_2

1.	A solution contains 0.1M H_2S and 0.3M HCI. If K_a and K_(a2) for H_2 S are 1 xx 10^(-7) and 1.3 xx 10^(-13) respectively, calculate concentration of HS^- and S^- in the mixture.
Answer» <html><body><p></p><a href="https://interviewquestions.tuteehub.com/tag/solution-25781" style="font-weight:bold;" target="_blank" title="Click to know more about SOLUTION">SOLUTION</a> :First ionisation, step 1 `,H_2 ShArr H^(+) +<a href="https://interviewquestions.tuteehub.com/tag/hs-492079" style="font-weight:bold;" target="_blank" title="Click to know more about HS">HS</a>^(-) """ K_a = 1 xx 10^(-<a href="https://interviewquestions.tuteehub.com/tag/7-332378" style="font-weight:bold;" target="_blank" title="Click to know more about 7">7</a>)` <br/> Second ionisation, step 2,`HS^(-)hArr H^(+)+s^(2-) "" K_(a_2) = 3 xx 10^(-13)` <br/> Presence of HCI supresses the dissociation of `H_2 S` due to common ion effect of `H^(+)`. <br/> For step `1,1 xx 10^(-7)= ([H^+][HS^(-)])/( [H_2 S])=(0.3[HS^(-)])/( 0.1)` <br/> Cocentrationof `HS^(-) `,`[HS^(-)])= 3.3 xx 10^(-<a href="https://interviewquestions.tuteehub.com/tag/8-336412" style="font-weight:bold;" target="_blank" title="Click to know more about 8">8</a>)mol L^(-1)`<br/> or step` 2,1,.3 xx 10^(-13) = ([H^+] [S^(2-)])/([HS^(-)]) = ( 0.3 [S^(2-)])/(3.3 xx 10^(-8))` <br/> concentrationof `s^(2-) , [S^(2-)] = 1.43 xx 10^(-20) mol L^(-1)`</body></html>