Answer : The incorrect statements are:
(A) When two nonmetals react, the compound formed is ionic.
(B) Two nonmetals can undergo an oxidation-reduction reaction.
Explanation :
Covalent compound : It is defined as the compound which is formed by the sharing of electrons between the atoms forming a compound.
The covalent compound are usually formed when two non-metals react.
The two nonmetals can not undergo an oxidation-reduction reaction.
Ionic compound : It is defined as the compound which is formed when electron gets transferred from one atom to another atom.
Ionic compound are usually formed when a metal reacts with a non-metal.
The metal-nonmetal reaction can always be assumed to be an oxidation-reduction reaction.
For example : 
In this reaction, sodium shows oxidation because the oxidation state changes from (0) to (+1) and and chlorine shows reduction because the oxidation state changes from (0) to (-1).
Hence, the incorrect statements are, (A) and (B)
Answer: 59 grams
Explanation:
According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.
Given: mass of hydrogen = 6.6 g
mass of oxygen = 52.4 g
Mass of products = Mass of hydrogen + mass of oxygen = 6.6 +52.4 = 59 g grams
Thus mass or reactant = mass of water
Mass of reactants = mass of products = 59 g
Thus the mass of water initially present was 59 g.
A spring - also an electromagnet. Also know as a slinky!
Noble gas notation for molybdenum:
[Kr] 4d^5 5s^1