$100$ mL solution of $NaOH$ (containing $4$ g $NaOH$ per litre) and $50$ mL of $HCl$ (containing $7.3$ g $HCl$ per litre) react as follows,
$NaOH\left(aq\right)+HCl\left(aq\right)⟶NaCl\left(aq\right)+H_{2}O\left(l\right)$
$0.5$ g of $NaCl$ is formed. Thus, unreacted $NaOH$ is:

Q. For the reaction : $Mn{O}_2+4HCl\stackrel{100\%}{\to }MnC{l}_2+C{l}_2+2H_{2}O$, $17.4gMn{O}_2$ is dissolved in $500mL$ of $HCl$ solution containing $7.3g$ $HCl$ per litre. (molar mass of $Mn=55g/mol$)

Q. A 200 millilitre aqueous solution of an acid (molar mass = 98) containing 58.8 g acid per litre is neutralized by 180 ml of aqueous NaOH solution completely. The NaOH solution containing $\frac{80}{3}$ g of NaOH per 500 ml of solution. Then find the basicity of the acid.

प्रति लीटर 58.8 g अम्ल (मोलर द्रव्यमान = 98) वाला 200 मिलीलीटर जलीय विलयन 180 ml जलीय NaOH विलयन द्वारा पूर्णतः उदासीन होता है। NaOH विलयन में प्रति 500 ml विलयन $\frac{80}{3}$ g NaOH है। तब अम्ल की क्षारकता ज्ञात कीजिए।

Q.

Q. $150g$ of a solution $(d=1.2g/ml)$ contains $63g$ of $HN{O}_3$. What volume of this $HN{O}_3$ (in mL) solution will be required to react with a $NaOH$ solution, containing $24g$ $NaOH$?
Reaction: $HN{O}_3+NaOH\to NaN{O}_3+H_{2}O$