Question

Please, bantuin jawab..Pakai cara yah.
Trimakasih.☺

Answer 1

8. pH = 5
pH = - log [H+]
[H+] = 10⁻⁵
[H+] = Ka x mol asam/mol garam
10⁻⁵ = 10⁻⁵ x (0,2x0,1) / mol garam
mol garam = 0,02 mol
massa  = 0,02 mol x 82 gr/mol = 1,64 gr  => jawabannya(B)

9. hidrolisis sebagian dan bersifat asam garam dari basa lemah dan asam kuat 
jawabannya (C)

10. M NaCN = 2,45 gr / 49 gr/mol  x  1000/500 = 0,1 M
[OH-] = √kw/ka x M
[OH-] = √10⁻¹⁴/7x10⁻¹⁰  x 0,1
[OH-] = 1/7¹/² x10⁻²·⁵
pOH = - log 1/7¹/² x10⁻²·⁵
pOH = 2,5 - log 1/7¹/²
pH = 14 - pOH
pH = 14 - (2,5 - log 1/7¹/² )
pH = 11,5 + log 1/7¹/²
pH = 11,5 + 1/2 log 1/7