Given the balanced equation for the oxidation of ethanol, c2h5oh, by potassium dichromate:

3 c2h5oh + 2 k2cr2o7 + 16 hcl > 3 c2h4o2 + 4 crcl3 + 4 kcl + 11 h2o
calculate the volume of a 0.600m k2cr2o7 solution needed to generate 0.1665 moles of c2h4o2 from a solution containing excess ethanol and hcl.

a) 278 ml b) 185 ml c) 111 ml d) 6.60 ml

The volume of a 0.600M K2Cr2O7 solution needed is 185 mL (option b)

Explanation:

C₂H₅OH + 2 K₂Cr₂O₇ + 16 HCl ---> 3 C₂H₄O₂ + 4 CrCl₃ + 4 KCl + 11 H₂O

In the reaction ratio between dichromate and acetic, is 2:3, so 3 moles of acetic came from 2 moles of dichromate.

We want to know, how many moles of K₂Cr₂O₇, we used.

3 moles C₂H₄O₂ 2 moles K₂Cr₂O₇

0.1665 moles  C₂H₄O₂ (0.1665  .2) / 3 = 0.111 moles

Solution of K₂Cr₂O₇ has a concentration of 0.6M

It means 0.6 moles in 1L of solution so, let's find the volume for 0.111 moles

0.6 moles are in 1 Liter

0.111 moles are in  (0.111  .1)/0.6 = 0.185 L

0.185 L to mL = 185 mL