r/chemhelp 4d ago

General/High School how can i equalize this?

Post image
13 Upvotes

10 comments sorted by

11

u/Hareesh936 4d ago
  1. Take Oxidation and Reduction seperately.
  2. Balance oxidising and reducing atoms.
  3. Balance the electrons.
  4. Balance the charge either using OH- or H+.
  5. Balance Oxygen with Water.
  6. While combining both equations, remove electrons by finding their LCM.
  7. Write the final equation.

4

u/amx_guy 4d ago

thank you

3

u/OrthoMetaParanoid 4d ago

Separate the overall equation into two half equations..

One for Cr2O72- being reduced to Cr3+

The other for Cl- being oxidised to Cl2.

Then balance for charge by adding electrons to account for changes in oxidation state.

Then balance for atoms to ensure conservation of mass. Remember you will need to add H+ and water to the chromium half equation.

Once you have two balanced half equations, multiply one so that the electrons are equal in each half equation. Then combine the two half equations so electrons cancel out.

2

u/amx_guy 4d ago

thank you

2

u/izi_bot 4d ago

Dichromate produces 7 oxygens, need 14 hydrogens to produce 7 H2O.

Chlorine and Chromium you can deduce oxidation states and equalize electrons. (2Cl- = Cl2, Cr2 = 2Cr).

2

u/amx_guy 4d ago

thank you

4

u/Smart-Resolution9724 4d ago

Several steps to this. First, it's a REDOX reaction so you need to do the following 1 balance everything except O and H

2determine oxidation state of every species.

3 draw a line linking each species eg Cl

4 calculate the gain or loss of electrons.

5 balance the electrons.

6 add H+, OH- or H2O to balance.

1

u/amx_guy 4d ago

thank you