anishaaas Posted March 19, 2016 Report Share Posted March 19, 2016 How do you go forward with this question? When the same quantity of electricity was passed through a dilute solution of sodium hydroxide and through a molten soluton of lead bromide, 0.100 mol of lead was produced. What amount (in mol) of hydrogen gas was evolved? A. 0.014 B. 0.050 C. 0.100 D. 0.200 Don't we need the Data Booklet for this one? Reply Link to post Share on other sites More sharing options...
kw0573 Posted March 19, 2016 Report Share Posted March 19, 2016 4 hours ago, anishaaas said: How do you go forward with this question? When the same quantity of electricity was passed through a dilute solution of sodium hydroxide and through a molten soluton of lead bromide, 0.100 mol of lead was produced. What amount (in mol) of hydrogen gas was evolved? A. 0.014 B. 0.050 C. 0.100 D. 0.200 Don't we need the Data Booklet for this one? Well assume the electrolysis reaction proceeds. There is either lead (II) bromide and lead (IV) bromide In dilute sodium hydroxide Cathode: 2H+ + 2e- --> H2 (Anode makes oxygen gas) If lead (II) bromide Cathode: Pb2+ + 2e- --> Pb (Anode makes bromine gas) Lead : hydrogen ratio is 1:1 ====> 0.100 mol of hydrogen gas. Choice C.If lead (IV) bromide Cathode: Pb4+ + 4e- --> Pb Now double the sodium hydroxide equation to match number of electrons 4H+ + 4e- --> 2H2 Lead : hydrogen ratio is 1: 2. ==> 0.200 mol of hydrogen gas. Choice D Note that predicting relative products quantity is in 19.1 of the chemistry guide. Molten solutions are covered in 9.2; dilute aqueous solutions are in 19.1. Reply Link to post Share on other sites More sharing options...
Msj Chem Posted March 20, 2016 Report Share Posted March 20, 2016 Maybe this video will help: Reply Link to post Share on other sites More sharing options...
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