Single bond: 1 pair of electrons
Double bond: 2 pairs of electrons
Triple bond: 3 pairs of electrons
Reaction of calcium with water
Calcium reacts slowly with water. This is in contrast with magnesium, immediately above calcium in the periodic table, which is virtually unreactive with cold water. The reaction forms calcium hydroxide, Ca(OH)2 and hydrogen gas (H2).
In a chemical reaction, there is a change in the composition of the substances in question; in a physical change there is a difference in the appearance, smell, or simple display of a sample of matter without a change in composition.
i think the answer is b) i.e. Switch....
according to me ammeter and battery are already there...
