Question

For the reaction 2 HCl + Ca ( OH ) 2 ⟶ CaCl 2 + 2 H 2 O how many grams of calcium hydroxide, Ca(OH)2, are needed to react completely with 57.7 g of hydrochloric acid, HCl?

Answer 1

Answer:

58.53 g of $Ca(OH)_{2}$ is need to react completely with 57.7 g of HCl.

Explanation:

Mass of HCl = 57.7g

Molecular mass of HCl= 36.46g/mol

Mass mass of $Ca(OH)_{2}$= 74.09g/mol

Calculationg mass of HCl,

$number of moles =\frac{mass}{molar mass}$

$number of moles =\frac{57.7g}{36.46g/mol}$

$number of moles= 1.58$ moles

As per the given equation,

$2HCl+Ca(OH)_{2} \rightarrow CaCl_{2} +2H_{2}O$

$2$ mol HCl$\rightarrow 1$ mol $Ca(OH)_{2}$

1.58 moles $HCl$ $\rightarrow x$ mol $Ca(OH)_{2}$

$x = \frac{1.58 mol HCl\times 1 mol Ca(OH)_{2} }{2 mol HCl}$

$x=0.79 mol Ca(OH)_{2}$

Now, calculating mass of $Ca(OH)_{2}$ from the above calculated moles,

$number of moles =\frac{mass}{molar mass}$

$mass of Ca(OH)_{2}= number of moles\times molar mass$

mass of $Ca(OH)_{2}$ $= 0.79mol\times 74.09g/mol$

mass of $Ca(OH)_{2}$$= 58.53g$.