How many moles of sodium hydroxide are needed to prepare 250 mL of a 0.85 M solution? A) 0.0034 B) 3.4 C) 210 D) 0.21

The moles of sodium hydroxide that are needed to prepare 250 ml of a 0.85 m solution is 0.21 Moles (answer D)

calculation

moles of sodium hydroxide is calculated using moles = molarity x volume in liters formula

where,

molarity = 0.85 M = 0.85 mol / L

moles = ?

volume = 250 ml convert into Liters

that is 1 L = 1000 Ml

? L = 250 ml

by cross multiplication

= (250 ml x 1 L) / 1000 ml = 0.25 L

moles is therefore = 0.85 mol/l x 0.25 L = 0.21 moles of sodium hydroxide