What volume of 0.20 mol dm -3 NaOH solution would yield 5.0 g of NaOH on evaporation to dryness? [NaOH = 40g mol-1]
Question 1 Report
What volume of 0.20 mol dm -3 NaOH solution would yield 5.0 g of NaOH on evaporation to dryness? [NaOH = 40g mol-1]
Answer Details
The first step is to calculate the number of moles of NaOH present in 5.0 g of the solution using the formula: Number of moles = mass ÷ molar mass The molar mass of NaOH is 40g mol-1. Therefore: Number of moles = 5.0 g ÷ 40g mol-1 = 0.125 mol Next, we use the formula: Number of moles = concentration x volume to calculate the volume of the NaOH solution needed to contain 0.125 mol of NaOH. Rearranging the formula gives: Volume = number of moles ÷ concentration Volume = 0.125 mol ÷ 0.20 mol dm-3 = 0.625 dm3 = 625 cm3 Therefore, the volume of 0.20 mol dm-3 NaOH solution needed to yield 5.0 g of NaOH on evaporation to dryness is 625 cm3. The correct option is (b) 625 cm3.
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