Question

30cm3 of NaOH is neutralised by 12.3cm3 of 0.2mol/l HCI. What is the concentration of the NaOH. 0.82 mol/l 0.082 mol/l 82 mol/l 0.49 mol/l

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Answer 1

Lets see

• C1V1=C2V2
• 30C1=0.2(12.3)
• 30C1=2.46
• C1=2.46/30
• C1=0.082mol/L

Answer 2

Step 1: Calculate the amount of sodium hydroxide in moles

• Amount of solute in mol = concentration in mol/dm 3 × volume in dm 3

• Amount of sodium hydroxide = 0.100 × 0.0250.= 0.00250 mol.

• The balanced equation is: NaOH(aq) + HCl(aq) → NaCl(aq) + H 2O(l)

• So the mole ratio NaOH:HCl is 1:1.