Question

What is the molarity of solution containing 10% by mass of calcium hydroxide in 0.5dm^3 of solution​

Answer 1

Answer:

The molarity of the solution is 0.27 molar.

Answer 2

$\mathbb{GIVEN}$

• mass percent = 10%
• Volume= 0.5 dm³ = 0.5 L
• Molar mass of Ca(OH)₂ = 40 + 32 +2 =74 g/mol

$\mathbb{TO \: FIND}$

• Molarity

$\mathbb{SOLUTION}$

Solution containing 10% by mass of calcium hydroxide means 10 g of calcium hydroxide is present in 100 g of solution.

Mass of Ca(OH)₂ = 10g

Molar mass of Ca(OH)₂ = 74 g/mol

$\begin{gathered}\to\tt{Moles \: of \: Ca(OH)_2= \dfrac{Mass \: of \: Ca(OH) _2}{molar mass \: of \: Ca(OH) _2}} \\\end{gathered}$

$\begin{gathered}\to\tt{Moles \: of \: Ca(OH)_2= \dfrac{10}{74}} \\\end{gathered}$

$\begin{gathered}\to\tt{Moles \: of \: Ca(OH)_2= 0.135} \\\end{gathered}$

• Now, as per the formula,

$\begin{gathered}\to\tt{Molarity= \dfrac{moles \: of \: Ca(OH) _2}{Volume \: of \: solution (L) }} \\\end{gathered}$

$\begin{gathered}\to\tt{Molarity= \dfrac{0.135}{0.5}} \\\end{gathered}$

$\begin{gathered}\to {\bf{Molarity= 0.27 \: molar}} \\\end{gathered}$

$\fbox{☛Molariry = {0.27} Molar }$