Substances have different tendencies to donate or accept electrons. When a really good donor meets a great acceptor, the chemical reaction releases a lot of energy. Oxygen (O2) is the best electron acceptor and is used in many aerobic reactions (reactions with oxygen). Hydrogen gas (H2) is a good electron donor.
When O2 and H2 are combined, along with a catalyst, water (H2O) is formed. This example of a redox reaction can be written like this:

Answer:
Option A = 1:1
Explanation:
The atoms of calcium and sulphur when react their ration is 1:1. The charge on calcium is +2 and on sulphur is -2.
Ca⁺²S⁻²
The +2 and -2 charges are cancel out and overall charge will be zero.
CaS
so their atomic ratio will be 1:1
They're based on the results of your testing.
Answer:
a) KOH
Explanation:
In the given balanced reaction
2K + 2H2O → 2KOH + H2
In the compound KOH,
The elements are K,O, and H and in the compound, there is one mole each of K , O ,and H.
So the element ratio here is 1 : 1 : 1.
