Question

What mass of ferric hydroxide is needed to prepare 500 mL of a 0.25N solution?

Answer 1

Explanation:

What mass of ferric hydroxide is needed to prepare 500 mL of a 0.25N solution?

Answer 2

The mass of ferric hydroxide is needed to prepare 500 mL of a 0.25N solution is

• In the solution of 500ml, 0.25 is the normality of NaOH solution. N is the symbol to show normality.
• Normality is the number of grams equivalent to solute present in 1 litre of solution.
• Several grams equivalent is equal to the gram of solute divided by equivalent weight.
• Equivalent weight is molecular weight divided by valency. so, the formula for normality is:
• $\frac{mass \: of \: solute \: \times 1000 \times n \: factor}{molecular \: mass \times volume \: in \: ml}$
• $\frac{normality \times molecular \: mass \times volume \: in \: ml }{1000 \times n \: factor} = mass \: of \: solute$
• n factor for ferric hydroxide is 3 because 3 electrons are exchanged in the overall reaction 3Fe3+ + OH- -------> Fe(OH)3.
• Putting values in the above equation get,
• $\frac{0.25 \times 3 \times 1000}{500 \times107 } = 0.014g$
• Henceforth, the mass of ferric hydroxide needed to prepare 500 mL of a 0.25N solution is 0.014g.