Question

Molarity of $HCl$ is (in multiples of $100$ (only single digit)) :

Answer 1

Let theb mass of ${Na}_{2}C{O}_3$ and $K_{2}C{O}_3$ in mixture be $a$ and $b$ g respectively.
$\therefore a+b=1...\left(i\right)$
For the given reaction :
Meq. of ${Na}_{2}C{O}_3$+ Meq. of $K_{2}C{O}_3$ = Meq. of $HCl$ $=$ Meq. of $AgN{O}_3$
$\frac{a}{\frac{106}{2}}\times 1000+\frac{b}{\frac{138}{2}}\times 1000=20\times N\times \frac{250}{5}$ $=16.24\times 0.1\times \left(\frac{250}{25}\right)...\left(ii\right)$
$\therefore N_{HCl}=0.0812or{M}_{HCl}=0.0812$ ($\because$ mono basic acid)
Also, strength of $HCl$ $=0.0812\times 36.5g{litre}^{-1}$ = $2.9638g{litre}^{-1}$
Also, by Eqs. (i) and (ii) : $a$ $=$ $0.4$ g; $b$ $=$ $0.6$ g ; $K_{2}C{O}_3$ in mixture = $60$
So, answer is $8$.