Which of the following chemical reactions is a redox reaction? NH4OH (aq) + KCl (aq) KOH (aq) + NH4Cl (aq)

Zn (s) + H2SO4 (aq) ZnSO4 (aq) + H2 (l)

H2SO4 (aq) + CaCl2 (aq) CaSO4 (aq)+ HCl (aq)

HBr (aq) + KOH (aq) KBr (aq) + H2O (l)

you need to stop taking that class

a. the law of proportion states the combination of 2 atoms in a specific ratio to produce multiple compounds such as the given statement of question ‘1st compound contains 88.8 % cu ’ indicates 88.8 g of cu is present along with 11.2 g oxygen in 100 g of compound whereas the statement ‘2st compound contains 79.9 % cu ’ indicates 79.9 g of cu is present along with 20.1 g oxygen in 100 g of compound

1st compound contains 88.8 g cu

for cu

m = 63 g /mol

atomic % = 88.8 /63 = 1.42

for o

m = 16 g /mol

atomic % = 11.2 /16 = 0.7

b. the emperical formula of 1st compound is

cu1.4o0.7

cu2o