Q: Calculate the unknown molar concentration of CH3NH2 in MeOH titrated against a known molar concentration of HCl ?

Could you please answer this, there are lots of examples around calculation PH of two known's but not so much of unknown concentration.

thankyou.

2 answers

If you had given some numbers it would have been easier; however, here is the procedure.
1. Write the equation and balance it.
CH3NH3 + HCl ==> CH3NH3Cl

2. mols HCl used = M HCl x L HCl = ?

3. mols CH3NH2 = same as mols HCl (since the equation is 1 mol CH3NH2 to 1 mol HCl).

4. M CH3NH2 = moles CH3NH2/L CH3NH2.
Done.
thanks, sorry,

10ml of the unknown mixture was titrated

methyl orange was used

it took 7.5ml of 1M HCl (.0074Mol ?)

so this means .00074Mol CH3NH2 / ml ?