A pH 4.10 Soln can be made by mixing HF and LiOH in water. What mass (g) of LiOH(s) must be added to 1L of 0.160M HF(aq) prepare in this solution. (Assume no volume change in addition of solid LiOH

Question

cuanchi · Answer

Are you familiar with the Henderson-Hasselbalch Approximation for a buffer?
pH=pKa+log([A−]/[HA])

you also will need the Ka of HF acid
Name	               Formula	        K a	                pKa
Hydrofluoric acid	HF	               6.3 × 10−4	3.20

anonymous · Answer

This is exactly what I used  using that I get 32 grams mass LiOH

anonymous · Answer

@cuanchi

cuanchi · Answer

I think that the value is a little high. Check your calculations. and let me know how did you do. You have there 1.3 mol LiOH in 32g and in your problem you have only 0.160 mol of HF acid. You will have excess of LiOH (1.3-0.160)=1.14 mol OH =>  pH> 14

anonymous · Answer

Yeah I understand the answer is wrong that's why I posted it. I've tried going over it and I get the same thing @cuanchi

cuanchi · Answer

how do you do? can you show me your steps