Answer: 
is a single replacement reaction.
Explanation:
A chemical reaction in which one element of a compound is replaced by another element is called single replacement reaction.
For example,
Here, fluorine element in the compound 
is replaced by the element bromine.
Therefore, it is a single replacement reaction.
Thus, we can conclude that is a single replacement reaction.
Answer:
2HgO → 2Hg + O₂
The reaction is a decomposition reaction because from one reactant two products were obtained
Explanation:
The problem here involves balancing the chemical reaction given and also classifying the reaction.
The unbalanced expression is given as:
HgO → Hg + O₂
Assign the alphabets a,b and c as coefficients that will balance the equation
aHgO → bHg + cO₂
Conserving Hg: a = b
O: a = 2c
So, let c = 1, a = 2 b = 2
Therefore;
2HgO → 2Hg + O₂
The reaction is a decomposition reaction because from one reactant two products were obtained
Polar liquids have both negative and positive ends.
