Which of the following is an oxidation-reduction reaction?
zns(s) + 2o2(> znso4(s)
cao(s) + h2o(l) > ca(oh)2(s)
6li2o(s) + p4o10(g) > 4li3po4(s)
so2(g) + h2o(l) > h2so3(aq)

Explanation:

The reaction is called redox reaction if there is oxidation and reduction in the reaction.

Oxidation is gain of oxygen, loss of hydrogen or loss of electrons.

Reduction is gain of hydrogen, loss of oxygen or gain of electrons.

a)

Here Zn is undergoing oxidation and oxygen is undergoing reduction. so it is an oxidation reduction reaction

b) In second reaction , the oxidation state of all elements remained the same. hence no oxidation reduction occur.

c) in third reaction also, the oxidation state of all elements remained the same. hence no oxidation reduction occur.

d) in fourth reaction also,the oxidation state of all elements remained the same. hence no oxidation reduction occur.

clouds form

solid ice forms on leaves.

water droplets form on grass.

"hydrogen bonding is the attraction of h atoms in the water molecule (slight + charge) to o atoms in a neighboring water molecule (slight - charge); it is a weak interatomic force. but it is still strong enough to the water molecules "stick" together."