The reactant is Mercury (II) Oxide while the products are Mercury and Oxygen separately.
This is because the reactants are typically always on the left side of the yields symbol. In this decomposition reaction, it would still be the same as at the end of the reaction, there were to products produced: Mercury and Oxygen.
Products tend to always be on the right side of the yields symbol, they're what comes out of a reaction no matter what type.
Hope this helps!
The Lewis bases are those which can donate electron pair to an acceptor. These electrons can be a pair of electron that is a lone pair, a negative charge or electrons in a 
-bond.
- In
, the presence of -bond make it a Lewis base. - In
, the presence of negative charge makes it a Lewis base. - In
, the presence of lone pair on nitrogen makes it a Lewis base. - In
, there is no lone pair, no -bond, no negative charge so it is not a Lewis base.
Hence, , , and are Lewis bases.
moles NaOH = c · V = 0.2753 mmol/mL · 43.44 mL = 11.959032 mmol
moles H2SO4 = 11.959032 mmol NaOH · 1 mmol H2SO4 / 2 mmol NaOH = 5.979516 mmol
Hence
[H2SO4]= n/V = 5.979516 mmol / 54.69 mL = 0.1093 M
The answer to this question is [H2SO4] = 0.1093 M
