A daniel cell constructed in the laboratory the voltage observed was 0.9v instead of 1.10v of the std cell a possible explanation is:
a) Molar ratio of Zn⁺², Cu is 2:1
b) The Zn electrode has thrice the surface of Cu electrode
c) [Zn⁺²]<[Cu²⁺]
d) [Zn⁺²]>[Cu²⁺]