28cm3 of 0.2mol of sodium hydroxide was titrated against 25cm3 of hydrochloric acid using methyl orange as indicator, calculate the concentration in mol/dm3,calculate the concentration in g/dm3
NaOH + HCl ==> NaCl + H2O
mols NaOH = ?
Look at the reaction equation. 1 mol NaOH = 1 mol HCl; therefore, mols HCl = mols NaOH.
Then mol/dm3 HCl = mols HCl/dm3 = ?
To find the concentration of sodium hydroxide (NaOH) in mol/dm^3, we can use the equation:
NaOH + HCl → NaCl + H2O
Since the equation is 1:1, the moles of sodium hydroxide (NaOH) is equal to the moles of hydrochloric acid (HCl).
Given:
Volume of NaOH solution (V1) = 28 cm^3
Molarity of NaOH solution (M1) = 0.2 mol/dm^3
Volume of HCl solution (V2) = 25 cm^3
First, let's convert the volumes of the solutions to dm^3:
V1(dm^3) = 28 cm^3 / 1000 = 0.028 dm^3
V2(dm^3) = 25 cm^3 / 1000 = 0.025 dm^3
Next, we can use the equation:
M1 * V1 = M2 * V2
Where:
M2 is the concentration of HCl in mol/dm^3 that we want to find.
Rearranging the equation, we have:
M2 = (M1 * V1) / V2
Substituting the values:
M2 = (0.2 mol/dm^3 * 0.028 dm^3) / 0.025 dm^3
M2 = 0.224 mol/dm^3
Therefore, the concentration of hydrochloric acid (HCl) is 0.224 mol/dm^3.
To find the concentration of sodium hydroxide (NaOH) in g/dm^3, we need to consider the molar mass of NaOH.
The molar mass of NaOH is:
(Mass of Na) + (Mass of O) + (Mass of H)
= (23 g/mol) + (16 g/mol) + (1 g/mol)
= 40 g/mol
Now, we can calculate the concentration in g/dm^3:
Concentration in g/dm^3 = (Concentration in mol/dm^3) * (Molar mass)
= 0.224 mol/dm^3 * 40 g/mol
= 8.96 g/dm^3
Therefore, the concentration of sodium hydroxide (NaOH) is 8.96 g/dm^3.