An erlenmeyer flask contains 25.00 ml of 0.500 m hcl before a titration is begun. how many moles of hydrogen ions are present in the flask at this time?
a) 0.0125
b) 12.5
c) 20.0
d) 50.0

A) 0.0125.

Explanation:

Molarity is the no. of moles of solute in 1.0 L of the solution.

M = no. of moles of HCl / V of the solution(L).

∴ no. of moles of HCl = M*V of the solution = (0.5 M)(0.025) = 0.0125 mol.

HCl → H⁺ + Cl⁻.

0.0125 mol of HCl contains 0.0125 mol of H⁺ and 0.0125 mol of Cl⁻.

So, the right choice is: A) 0.0125

A is right on e 2020