H2A is a weak diprotic acid. If the pH of 0.1 M H2A solution is 3 and concentration of A2- is 10-12 at 25°C. Select correct statement(s)

H2A⇌H++HA−∵y is very less so x+y≈x∴Ka1=x2c−xAt equilibrium  C- X x+y x−y Ka2=y=10−12;pKa2=12HA−1⇌H++A2− at equilibrium  x−y x+y ypKa2−pKa1=12−5=7pH=12pKa1−logC3=12pKa1+1pKa1=5