[nu_paradigm]

Hello there... I have a few problems in ionic equilibrium....

1. Calculate pH of mixture containing 50 ml 0.1 M NaOH and 0.1 M CH3CHOOH. Given Ka = 1.9 * 10^ -5   (Ans= 12.3979)

I tried by using the regular salt of weak acid + strong base method. By finding the conc. of salt formed CH3COONa, i.e, 0.05 M and then using the formula
pH= 7+ 1/2 pKa+ 1/2 logC, C being conc. of salt.
But the answers don't match.

2. A solution is saturated with respect to SrCO3 and SrF2. The conc of CO3 ^2- was found to be 1.2 * 10^ -3 M. The conc of F^- in the solution wud be?     (Ans= 3.7 * 10 ^ -2 M)

I need the approach. I know the common ion effect is at work. How will we proceed?


I need the answers at the earliest... please help.

[AWK]

1. Your answer is wrong. PH sholud be close to 9

2.
a. Calculate concentratiopn of Sr(2+) from concentration of CO3(2-) and Ksp of SrCO3
b. Put this number to Ksp of SrF2 and calculate concentration of F(-)

[rajajidwivedi]

i dont think that answer given by you is right

[Borek]

Man, this is a SIX years old thread, it stinks like a zombie.