Question

Trộn V lít dd HCl 0,2M với 1l dd NaOH 0,1M đc dd có pH=2,3. Tính V

Answer 1

\(n_{NaOH}=1.0,1=0,1\left(mol\right)=>n_{OH^-}=0,1\left(mol\right)\)

\(n_{HCl}=0,2.V\left(mol\right)=>n_{H^+}=0,2.V\left(mol\right)\)

\(pH=-log\left(H^+\right)\)

=> \(C_{M\left(H^+\right)}=0,005M\)

=> \(n_{H^+\left(dư\right)}=0,005.\left(V+1\right)\left(mol\right)\)

PTPL: \(H^++OH^-\rightarrow H_2O\)

_____0,1<----0,1____________(mol)

=> \(n_{H^+\left(dư\right)}=0,2.V-0,1\left(mol\right)\)

=> \(0,2.V-0,1=0,005.\left(V+1\right)\)

=> V = 0,5385 (l)