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Question 1

A solution of sodium hydroxide contained 0.250 mol dm^-3. Using phenolphthalein indicator, titration of 25.0 cm³ of this solution required 22.5 cm³ of a hydrochloric acid solution for complete neutralisation.

1. write the equation for the titration reaction.
2. what apparatus would you use to measure out (i) the sodium hydroxide solution? (ii) the hydrochloric acid solution?
3. what would you rinse your apparatus out with before doing the titration ?
4. what is the indicator colour change at the end-point?
5. calculate the moles of sodium hydroxide neutralised.
6. calculate the moles of hydrochloric acid neutralised.
7. calculate the concentration of the hydrochloric acid in mol/dm³(molarity).

Question 2

A solution made from pure barium hydroxide contained 2.74 g in exactly 100 cm³ of water. Using phenolphthalein indicator, titration of 20.0 cm³ of this solution required 18.7 cm³ of a hydrochloric acid solution for complete neutralisation. [atomic masses: Ba = 137, O = 16, H = 1)

1. write the equation for the titration reaction.
2. calculate the molarity of the barium hydroxide solution.
3. calculate the moles of barium hydroxide neutralised.
4. calculate the moles of hydrochloric acid neutralised.
5. calculate the molarity of the hydrochloric acid.

Question 3

25 cm³ of a solution of 0.1 moldm^-3 NaOH reacts with 50 cm³ of a solution of hydrochloric acid. What is the molarity of the acid?

Question 4

25.0 cm³ of a 0.10 moldm^-3 solution of sodium hydroxide was titrated against a solution of hydrochloric acid of unknown concentration. 27.3 cm³ of the acid was required. What was the concentration of the acid?

Question 5

10 cm³ of a solution of NaCl react with 15 cm³ of  a 0.02 moldm^-3 solution of AgNO₃. What is the concentration of the NaCl solution in gdm^-3?

Question 6

25 cm³ of a 0.1 moldm^-3 solution of an acid H_xA reacts with 75 cm³ of a 0.1 moldm^-3 solution of NaOH. What is the value of x?

Equation: H_xA + xNaOH à + Na_xA + xH₂O

Question 7

A solution of hydrochloric acid of volume 25.0 cm³ was pipetted onto a piece of marble which is calcium carbonate. When all action had ceased, 1.30g of the marble had dissolved. Find the concentration of the acid

Equation: CaCO₃ + 2HCl à CaCl₂ + CO₂ + H₂O

Question 8

What volume of 0.1 moldm^-3 hydrochloric acid would be required to dissolve 2.3 g of calcium carbonate?

Equation: CaCO₃(s) + 2HCl(aq) à CaCl₂(aq) + CO₂(g) + H₂O(l)

Question 9

2.05 g of the carbonate of an unknown alkali metal (X₂CO₃) required 8.9 cm³ of 2.0 moldm^-3 hydrochloric acid to completely dissolve it. What was the relative atomic mass of the metal and which metal was it?

Equation: X₂CO₃(s) + 2HCl(aq) à 2XCl(aq) + CO₂(g) + H₂O(l)

Question 10

3.2 g of hydrated sodium carbonate, Na₂CO₃.xH₂O, was dissolved in water and the resulting solution was titrated against 1.0 moldm^-3 hydrochloric acid. 22.4 cm³ of the acid was required. What is the value of x?