CHem acidic environment question (1 Viewer)

[lazyandcool]

A cleaning agent contains a weak base of general formula NAX,1.00g of this compound was dissolved in 100 ml of water . A 20 ml sample of the solution was Titrated with 0.1000 mol/L HCL and required 24.4 mL for neutralization.what is molar mass of this base?

 

[jamesfirst]

HCl + NaX -> NaCl + H2O

HCl: n = cV
= 0.1000 M x 0.0244 L
= 0.00244 mol

NaX: 0.00244 mol (From the equation, the mole ratio is 1:1)

n (base) in 100mL = 0.00244 x 5
= 0.0122 mol

M (base): M = m/n
= 1 g / 0.0122 mol
= 82.0 g

 

[lazyandcool]

How did you find n(base) in 100 ml where did X5 came from in second step

 

[jamesfirst]

Because it needs 100ml of base to neutralise 1 mole of HCl in 100ml of water. (they have the same mole, so their volume is same - Gay Lussac's law)


so you need 5 times of 20mL of base to neutralise 1 mole of HCl


I guess it relates back to titration. It needs the same mole of base and acid to reach the equivalence point hence neutralising the acid