Answer:
10

Explanation:
Isolate the variable by dividing each side by factors that don't contain the variable.
I think it’s C since the ice changes from solid to a liquid which is physical and then it reacts with calcium metal making the calcium hydroxide which is chemical change. And another sign of it being chemical was the release of gas.
Answer : The correct option is, 
Explanation :
- Oxidation reaction : It is defined as the reaction in which a substance looses its electrons. That means, the loss of electrons takes place.
Or we can say that, oxidation reaction occurs when a reactant losses electrons in the reaction.
- Reduction reaction : It is defined as the reaction in which a substance gains electrons. That means, the gain of electrons takes place.
Or we can say that, reduction reaction occurs when a reactant gains electrons in the reaction.
According to the electrochemical series,
most likely to be reduced because
Hence, the ion most likely to be reduced is
.