your answer will be :
B. <u>Na has a lower</u> <u>electronegativity than H</u>
because Na belongs to alkali metals which are least electronegative (most electro positive) but hydrogen is a non metal, it has higher electronegativity as compared to metals like Sodium (Na).
Answer:
Ammonia is the richest source of nitrogen on a mass percentage basis because it has 82.35% of nitrogen by mass.
Explanation:
Percentage of element in compound :

(a) Urea, 
Molar mass of urea = 60 g/mol
Atomic mass of nitrogen = 14 g/mol
Number of nitrogen atoms = 2

(b) Ammonium nitrate, 
Molar mass of ammonium nitrate = 80 g/mol
Atomic mass of nitrogen = 14 g/mol
Number of nitrogen atoms = 2

(c) Nitric oxide, NO
Molar mass of nitric oxide = 30 g/mol
Atomic mass of nitrogen = 14 g/mol
Number of nitrogen atoms = 1

(d) Ammonia, 
Molar mass of ammona = 17 g/mol
Atomic mass of nitrogen = 14 g/mol
Number of nitrogen atoms = 1
Ammonia is the richest source of nitrogen on a mass percentage basis because it has 82.35% of nitrogen by mass.
<h3>
Answer:</h3>
0.75 moles NaOH
<h3>
Explanation:</h3>
We are given;
Volume of NaOH solution = 2.5 Liters
Molarity of NaOH = 0.300 M
We are required to calculate the moles of NaOH
We need to establish the relationship between moles, molarity and volume of a solution.
That would be;
Concentration/molarity = Moles ÷ Volume
Therefore;
Moles = Concentration × Volume
Thus;
Moles of NaOH = 0.300 moles × 2.50 L
= 0.75 moles
Therefore, the number of moles of NaOH is 0.75 moles