We can solve this problem using the long hand solution, wherein we 1 by 1 analyze the different equilibrium reactions or by simply using the Henderson Hasselbach equation. The equation is
pH = -log(pKa) + log (salt/acid)
since the acid and the salt have the same concentration, the log (salt/acid) term is equal to zero.
thus
pH = -log(1.73*10-5)
pH = 4.76
please be careful with the negative sign
Salt!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
The total charge of a compound must be zero. So the Y ion has charge of -2. Then the charge of X ion+(-2)*2=0. So the charge of X ion is +4.