You are provided with solutions UU and VV: Pour about 2 cm 3 of solution UU into a test tube; add 2 to 3 drops of methyl orange (MO) indicator to test whether it is an acidic or basic solution. Empty the test tube and wash it. Repeat the procedure using solution VV. The acidic solution you have identified is a solution of 0.1 M nitric acid. The basic solution was made by dissolving 2.65 g of Na2CO3 in a 0.5 dm3 of a solution. Titrate the acid solution (from the burrete) against the base solution (in titration flask) using methyl orange (MO) as an indicator up to the end point. Repeat the procedure to obtain three more burrete readings. Record your results in a tabular form.

1. Calculate the average titre volume. (0 alama)
2. The value of x and hence replace it in the formula Na2CO3.xH2O (0 alama)
3. Write a balanced chemical equation for the reaction between UU and VV. (0 alama)
4. What is the significance of the indicator in this experiment? (0 alama)

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Determine the effect of concentration on the rate of chemical reaction. The chemicals provided are C which contained 10.0 g of sodium thiosulphate in 500 cm3 litre of solution and H which contained 2 M nitric acid solution. You are also given a stopwatch and a piece of white paper marked X and distilled water. Provided as follows (i) Place a 100 cm3 beaker on top of cross X on the plain paper such that the cross X is visible through the mouth of the beaker when viewed form above. (ii) Measure 25 cm3 of C and pour it into a beaker in step (i). (iii) Measure 5 cm3 of H and pour it into a beaker containing C in step (ii) and instantly start the stop watch. (iv) Stear the mixture with a glass rod while keep on observing the cross from above: record the time taken for the cross to dissapear completely. (v) Repeat the procedures (ii) – (iv) for different concentration of C as indicated in the following table. Table: Experimental Data Time taken for the Volume of C Distilled Volume of H cross to disappear (cm3) water (cm3) (cm3) (sec). 25 0 5 20 5 5 15 10 5 10 15 5 5 20 5

1. Place a 100 cm³ beaker on top of cross X on the plain paper such that the cross X is visible through the mouth of the beaker when viewed form above. (1 alama)
2. Complete filling the Table. (0 alama)
3. Measure 25 cm³ of C and pour it into a beaker in step (i). (1 alama)
4. What does the shape of the graph indicate? (0 alama)
5. Write the ionic equation for the reaction between C and H. (0 alama)
6. Why did the cross X disappear? (0 alama)
7. From the graph, what do you conclude about the effect of increasing concentration on the rate of reaction? (0 alama)

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