In an experiment to study the reactivity of Ru(s), Tl(s), Gd(s) and V(s), a student observed the reactions.

Tl(s)+Ru3+(aq)→Ru(s)+Tl3+(aq)

Tl(s)+Gd3+(aq)→ no evidence of a reaction

Ru(s)+V3+(aq)→V(s)+Ru3+(aq)

use the above information to find the answer to the question below 

another spontaneous reaction that would occur is

Select one:

V(s)+Tl3+(aq)→Tl(s)+V3+(aq)

Gd(s)+Ru3+(aq)→Ru(s)+Gd3+(aq)

Ru(s)+Tl3+(aq)→Tl(s)+Ru3+(aq)

V(s)+Gd3+(aq)→Gd(s)+V3+(aq)

question 2 

An electrochemical change occurs when a strip of nickel is immersed in an acidified solution that contains dichromate ions.

The colour change that occurs as the reaction above proceeds is:

Select one:

Green to colourless

Green to orange

Orange to green

Colourless to green