Kak tolong bantuannya
Penjelasan:
a. 200 ml NH3 0,1 M dengan 100 ml HCl 0,1 M.
Mol NH3 = M x V = 0,1 x 200 = 20 mmol
Mol HCl = 0,1 x 100 = 10 mmol
Persamaan Reaksi:
NH3 + HCl —> NH4Cl
20 10 –
10 10 10 mmol
10 – 10 mmol
basa lemah bersisa, larutan garamnya bersifat penyangga basa.
[OH-] = Kb x mol basa / mol garam
= 10^(-5) x 10 / 10
= 10^(-5)
[H+] = Kw / [OH-]
= 10^(-14) / 10^(-5)
= 10^(-9) M
pH = 9
b. 150 ml CH3COOH 0,1 dengan 100 ml NaOH 0,1 m
mol CH3COOH = 0,1 x 150 = 15 mmol
mol NaOH = 0,1 x 100 = 10 mmol
persamaan reaksi:
CH3COOH + NaOH —> CH3COONa + H2O
15 mmol 10 –
10 10 10 mmol
5 mmol – 10 mmol
asam lemah bersisa, garamnya bersifat penyangga asam.
[H+] = Ka x mol asam / mol garam
= 10^(-5) x 5 / 10
= 0,5 x 10^(-5)
= 5 x 10^(-6)
pH = 6 – log 5