(b)Electric current was passed through a solution of sodium hydroxide using platinum electrodes. Draw a labelled electrolytic cell for this electrolysis. Indicate the directions of the movement of ions.
9.Two experiments were carried out using the same mass of magnesium ribbon and the same volume of acids of the same concentration. The acids were 1M hydrochloric acid and 1M ethanoic acid. The results were as shown in the following figure:
(a)If the experiments were conducted within the same time, is there a difference in volumes of hydrogen gas collected at the same room temperature and pressure? Give reasons for your answer.
(b)When same mass, volume and concentration of powdered magnesium and ethanoic acid are allowed to react, new graph is formed. Giving reason (s), suggest the position of that graph whether will be above, between or below graphs A and B.
(b)Lack of safe water for domestic and industrial uses is a serious problem in most of Tanzanian towns. The major cause of this problem is pollution in the water sources. Slate three methods that could make water from a pond or a well be safe for drinking.
11.(a) The chemical properties of concentrated sulphuric acid can be grouped into oxidizing property and dehydrating property. In which property should sulphuric acid be grouped when it reacts with copper metal? Give reason and write the equation of the reaction.
(b) The preparation of chlorine gas can be represented by the following equation: MnO2 + 4HCl ? MnCl2 + 2H2O + Cl2. Calculate the number of moles of HCl which are needed to react with 20 g of MnO2 and list two main chemical properties of chlorine gas.
12.Consider a four carbon hydrocarbon (C4Hn), where n is an integer. Give the name of homologous series, molecular formula and structural formula for different isomers of the compound formed by each homologous. In each case indicate the causes of isomerism.