Ionic compound are those compounds which are made up of ions. The ion which has tendency to loose electrons is said to cation (positive charge) such as metals whereas ion which has tendency to gain electrons is said to anion (negative charge) such as non-metals.
Calcium nitrate is quite soluble in water due to very low lattice enthalpy in comparison to other ionic compound. With lower lattice enthalpy, less energy is required for the dissociation of calcium nitrate and it get dissolves in water than other three compounds. Moreover, hydration energy is higher for calcium nitrate which make its solubility higher in water than other ionic species.
Thus, 
is correct answer.
The number of moles for co2=mass(g)/molar mass
n=.22/44=.005 mole of CO2
from the equation we see the relationship between the moles of co2 and O2 and we find that they have the same number of moles
So we need .005mole of O2
Multiple the number of moles with avogadro’s number to know the number of O2molecules
.005x6.022 x10^23
The main functions of the cell wall are to provide structure, support, and protection for the cell.
In a titration process, the unknown or the analyte with a known volume is placed in a flask and the titrant whose concentration is known is placed in the burette. The indicator in the titration process is generally added to the flask with the analyte.
