Jump to content
Sign in to follow this  

Redox reactions paper 1 question, help!

Recommended Posts

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?

Share this post


Link to post
Share on other sites
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- --> H(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- --> 2H
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.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this  

×
×
  • Create New...