Formatting page ...
STD. 10 A&B NARBHERAM HANSRAJ ENGLISH SCHOOL BISTUPUR, JAMSHEDPUR PRE-BOARD 20% TEST 2015-16 CHEMISTRY F.M.20 Q1. 40cm3 of methane reacts with chlorine. Calculate the volume of HCl gas formed and chlorine gas required (Balanced equation has to be written) [3] Q2. A sample of coal gas contained 45% H2, 30% CH4 , 20% Co and 5% C2H2 by volume. 100ml of this gaseous mixture was mixed with 160 ml of oxygen and exploded. Calculate the volume and the composition of the resulting mixture. When cooled to room temperature and pressure. [4] Q3. The following is a sketch of an electrolytic cell used in the extraction of aluminium. i) ii) iii) iv) [4] What is the substance of which the electrodes A & B are made ? At which electrode (A or B) is the aluminium formed. What are the two aluminium compounds in the electrolyte C. Write names with formula. Why is it necessary for electrode B to be replaced continuously ? Q4. Write the cell reactions for the following :i) Electrolysis of conc. Solution of CuSO4 (Cu electrodes) ii) Dilute AgNO3 solution using Ag anode and Cu cathode. Equations must be shown in details. Q5. Give reasons for the following :[5] i) Electrolysis of molten lead bromide is considered a reaction in which oxidation and reduction i.e. a redox reaction occurs. ii) The blue colour of aqueous copper sulphate fades when it is electrolysed using platinum electrodes. iii) Lead Bromide undergoes electrolytic dissociation in the molten state but is a non-electrolyte in the solid state. iv) Aluminium is extracted from its oxide by electrolytic reduction and not by conventional reducing agents. v) The volume of hydrogen and oxygen formed at the cathode and anode are 2 :1 by volume respectively. ****** [4]
|
