You are provided with:

- Solution A that is a mixture containing two bases , sodium hydroxide (NaOH) and sodium carbonate (Na2CO3) solids, dissolved in a 1000cm3 solution.

- Solution B which is 0.2M hydrochloric acid.

- Phenolphthalein and methyl orange indicators

- Solution C which is barium chloride solution.

You are required to determine the concentration of each of the reactants in the mixture.

Procedure (I)

- Pipette 25.0cm3 of solution A into a conical flask.

- Add 3 drops of methyl orange indicator.

- Titrate solution A with solution B until the yellow colour just changes to pink.

- Record your results in the table I below.

- Repeat the procedure to obtain at least two concordant readings. (3mks)

Table I

Questions

a) Calculate the average volume (V) of solution B used. Show your working (1mk)
b) Calculate the number of moles of acid that reacted (2mks)

Procedure II

- Pipette 25.0cm3 of solution A into a conical flask. Measure 15.0cm3 of Barium chloride solution (solution C) with a clean measuring cylinder. Add it to the solution A in the conical flask. Shake it gently and add 3 drops of phenolphthalein indicator.

- Titrate solution B into the conical flask until the pink colour just changes to colourless. N/B: The white precipitate should remain in the flask

- Record your results in the table II below.

- Repeat the procedure to obtain at least two concordant readings (3mks)

Table II

c) Calculate the average volume V2 of solution B used. (Show your workings) (1mk)
d) The equation for the formation of white precipitate

During titration II the white precipitate formed after adding Barium chloride does not take part in the titration but all the hydroxide ions (OH-) in solution are neutralized.

i) Calculate the moles of acid (solution B) reaction of titration II (2mks)

ii) Calculate the moles of sodium hydroxide (OH-) reacting during the titration. (2mks)

e) Calculate the number of moles of acid that reacted with sodium carbonate in the mixture. (2mks)

f) Calculate the molarity of solution A in terms of sodium hydroxide (NaOH) (2mks)

g) Write an ionic equation for the reaction of the acid with sodium carbonate. (2mks)

i) Calculate the number of moles of sodium carbonate in the mixture (1mk)

ii) Calculate the molarity of solution A in terms of sodium carbonate. (1mk)

You are provided with;

- Various water samples M, N, P and R.

- Soap solution.

You are required to;

Perform a lather test and hence determine the softness of water samples.

Procedure

Fill the burette up to the mark with the soap solution provided.

Pipette 25cm3 of solution R into a conical flask.

Add 2cm3 of soap solution from the burette .

Shake the mixture and note whether persistent lather forms.

If lather does not form add more soap solution from the burette until it forms.

Enter your results in the table below.

Repeat the procedure with each of the remaining solution each time rinsing the apparatus thoroughly between successive experiments (3mks)

a) Table

b) Which sample is likely to be:

(i) River water (1mk) .....................................................................................................................................

(ii) Sea water (1mk) .....................................................................................................................................

(iii) Rain water (1mk) .....................................................................................................................................

(iv) Distilled water (1mk) .....................................................................................................................................

Which samples can be classified as:

i) Soft water (1mk)

.....................................................................................................................................

ii) Hard water (1mk)

.....................................................................................................................................

You are provided with solid A.

You are required to carry out the tests shown below and write your inferences in the spaces provided. Identify any gases given out.