-ideal gas: a hypothetical gas whose molecules exhibit no interaction and undergo elastic collision with each other and the walls of the container
-macroscopic properties: properties that can be visualized or measured by the naked eye; examples include pressure, temperature, and volume
Answer : The correct answer for molarity of MgCl₂ solution is 0.67 M.
Molarity :
It expresses concentration of any solution . It can be defined as mole of solute present in volume of solution in Liter .
It uses unit M or 
It can be formulated as :

Given : mol of MgCl₂ (solute ) = 0.50 mol
Volume of solution = 750 mL
Following steps can be done :
Step 1 ) To convert volume of solution from mL to L
1 L = 1000 mL

Volume of solution = 0.750 L
Step 2) To find molarity
Plugging mole of solute and volume of solution in molarity formula as :


Hence molarity of MgCl₂ solution is 0.67 M
Answer:
Dissociation of O-H bond is highly favorable in p-cyanobenzoic acid resulting to higher acidity as compared to m-cyanobenzoic acid.
Explanation:
In p-cyanobenzoic acid, adjacent carbon to carboxyl group (-COOH) gets a partial positive charge due to electron withdrawing resonating effect of carboxyl group as compared to m-cyanobenzoic acid.
Due to this partial positive charge on carbon atom in p-cyanobenzoic acid, O-H bond in -COOH group remains highly polarized towards oxygen atom. Hence, dissociation of O-H bond is highly favorable in p-cyanobenzoic acid resulting to higher acidity as compared to m-cyanobenzoic acid.
Resonance structures are given below.
Molar Mass: 300.0510 g/mol