Which equation describes the half-reaction that occurs at the cathode during the electrolysis of water? 4h+(aq + 4oh–(aq ? 4h2o(l 2h2o(l ? 2h2(g + o2(g o2(g + 4h+(aq + 4e– ? 2h2o(l 2h2o(l + 2e– ? h2(g + 2oh–(aq?

Explanation :

Electrolysis of water is defined as decomposition of water into oxygen gas and hydrogen gas due to the passage on an electric current. In electrolytic cell oxidation occurs at anode and reduction occurs at cathode. At anode we will get oxygen gas and at cathode we will get hydrogen gas.

Half reaction at anode:

..(1)

Half reaction at cathode:

..(2)

Overall reaction:(1)+(2)

i think it's c. if you look search electronic symbol on google and then click on wiki it shows you a

considering the question as per the attachment

here we can see that the radon nuclide has 222 as the atomic mass number and 86 as the atomic number.

when it undergoes nuclear fission it gives polonium which has atomic mass number as 218 and atomic number will be 84 along with a helium nucleus which has 4 atomic mass number and 2 as its atomic number.

222 = 218 + 4 (atomic mass number)

86 = ? + 2; therefore ? = 86-2 = 84.

the atomic mass number of polonium will be 84.