Answer:
B) we will convert the 10 g of NaCl into moles.
Explanation:
Molarity is used to describe the concentration of solution. It tells how many moles are dissolve in per litter of solution.
Formula:
Molarity = number of moles of solute / L of solution
we will convert the 10 g of NaCl into moles.
Number of moles of NaCl:
Number of moles = mass/molar mass
Number of moles = 10 g/ 58.44 gmol
Number of moles = 0.17 mol
1 Kg = 1 L
Molarity = 0.17 mol / 2 L
Molarity = 0.085 mol/L
Molarity = 0.085 M
option A.
The number of valence electrons of an element can be determined by the periodic table group (vertical column) in which the element is categorized
Answer : The limiting reagent is 
Solution : Given,
Moles of methane = 2.8 moles
Moles of
= 5 moles
Now we have to calculate the limiting and excess reagent.
The balanced chemical reaction is,

From the balanced reaction we conclude that
As, 2 mole of
react with 1 mole of 
So, 5 moles of
react with
moles of 
From this we conclude that,
is an excess reagent because the given moles are greater than the required moles and
is a limiting reagent and it limits the formation of product.
Hence, the limiting reagent is 
I think it will be B. Hope it helps :)
Answer:
A
Explanation: The definition of a compound is two elements chemically connected