Question

Identify which redox reactions occur spontaneously in the forward direction.

Check all that apply.

	2Ag+(aq)+Ni(s)→2Ag(s)+Ni2+(aq)
	2Cr(s)+3Pb2+(aq)→2Cr3+(aq)+3Pb(s)
	Ca2+(aq)+Zn(s)→Ca(s)+Zn2+(aq)
	Sn(s)+Mn2+(aq)→Sn2+(aq)+Mn(s)

Answer 1

This is based on the fact that
more reactive metal can replace less reactive metal from its salt solution
take metal reactivity series ,

Ca > Mn> Zn > Cr > Ni > Sn > Pb > Ag

Ca is most reactive it can replace others from their salt
Ag is least reactive So it can not replace other metals,
So

2Ag+(aq) + Ni(s)→2Ag (s) + Ni2+ (aq) . It occur spontaneously,because Ni
is more reactive********

2Cr(s)+3Pb2+(aq)→2Cr3+(aq)+3Pb(s) . it occur spontaneously , because Cr
is more reactive *************.

Ca2+(aq)+Zn(s)→Ca(s)+Zn2+(aq) . It can not happen spontaneously, because
Zn is less reactive.

Sn(s)+Mn2+(aq)→Sn2+(aq)+Mn(s) . It can not happen spontaneously, because
Sn is less reactive

Thank you !.