The mass of potassium hydroxide required to make 300.ocm3 of 0.4 moldm-3 solution is {KOH = 56.0}

  • A 26.88g
  • B 13.44g
  • C 6.72g
  • D 3.36g
waec 2016chemistry

The correct answer is C. 6.72g

300cm3 of 0.4moldm3

1000cm3 contains 0.4mole

300cm3 will contain \(\frac{300 \times 0.4}{1000}\)

= 0.12mole

Number of moles = \(\frac{Mass}{\text {Molecular mass}}\)

Mass = number of moles x m.mass

= 0.12 x 56 = 6.72g

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