Question

what mass of sodium hydroxide will neutralize completely 3.612 mol of hcl?
3.612 g
0.09030 g
144.5 g
11.07 g

Explanation:

Step1: Write the balanced chemical equation

The reaction between NaOH and HCl is $NaOH + HCl=NaCl + H_2O$. The mole - ratio of NaOH to HCl is 1:1.

Step2: Determine the moles of NaOH

Since the mole - ratio of NaOH to HCl is 1:1, if we have 3.612 mol of HCl, the moles of NaOH required for complete neutralization is also 3.612 mol.

Step3: Calculate the molar mass of NaOH

The molar mass of Na ($M_{Na}=22.99\ g/mol$), O ($M_O = 16.00\ g/mol$) and H ($M_H=1.01\ g/mol$). The molar mass of NaOH, $M_{NaOH}=22.99 + 16.00+1.01=40.00\ g/mol$.

Step4: Calculate the mass of NaOH

We use the formula $m = n\times M$, where $n$ is the number of moles and $M$ is the molar mass. Substituting $n = 3.612\ mol$ and $M = 40.00\ g/mol$ into the formula, we get $m=3.612\ mol\times40.00\ g/mol = 144.48\ g\approx144.5\ g$.

Answer:

144.5 g