Question

How many mL of 1.20M HCL would it take to just exhaust 100.mL of a buffer that is 0.300M in HCO3^- and 0.200M in CO3^2-? a) Write the balanced net ionic reaction that occurs when HCl is added?

Answer 1

HCO3^- (aq) + HCl(aq) ------> H2CO3(aq) ----> H2O(l)+ CO2(g)

1Mole of HCl require to neutralize 1 mole of HCO3^-

Concentration of HCO3^- = 0.3M

No of mole of HCO3^- in 100ml = 0.03 mole

So, No of mole of HCl required = 0.03 mole

CO3^2-(aq) + 2 HCl(aq) ----> H2CO3(aq)-----> H2O(l) + CO2(g)

2mole of HCl neutralize one mole of CO3^2-

Concentration of CO3^2- = 0.2M

No of moles CO3^2- in 100ml = 0.02mole

No of mole of HCl required = 0.04 mole

Total no of mole HCl required = 0.07 mole

Concentration of HCl = 1.20M

no of mole in 1 ml of HCl = 0.001mole

Total mole of HCl required = 0.07 mole

Therefore, volume of HCl required = 70ml