Question

Calculate molarity of 5g of NaOH is dissolved in 450cm^3 of water .​

Answer 1

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Calculate the molarity of 5g of NaOH is dissolved in 450 $\large{cm}^{3}$ of water?

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Given that

Mass of NaOH = 5 grams

Volume of water= 450 ${cm}^{3}$

Molar Mass of NaOH= 23+16+1 =40 grams

Number of moles=

$\frac{mass \: of \: sodium \: hydroxide}{molar \: mass} \\ \\ = \frac{5}{40} \\ \\ = \frac{1}{8}$

$molarity = \frac{no \: of \: moles \: of \: solute}{volume \: of \: solution(in \: litres)} \\ \\ = \frac{ \frac{1}{8} }{0.450} \\ \\ \\ = \frac{ \frac{1}{8} }{ \frac{450}{1000} } \\ \\ \\ = \frac{1000}{450 \times 8} \\ \\ \\ = \frac{125}{450} \\ \\ \\ = 3.6 \: mol \: {litres}^{ - 1}$

Points to remember

• Use correct formula
• Convert all units same