Adding salt to water when boiling vegetables or pasta makes the water boil at a higher temperature. How much would the boiling point of water be increased if 49.2 g of NaCl is added to 500 mL of water?

1 Answer
anor277
May 11, 2018

Well, you have omitted a crucial piece of info....

Explanation:

...the ebullioscopic constant...for water, this is #K_b=0.512*K*kg*mol^-1#...the units are #"Kelvin, kilograms per mole of PARTICLES"#...and here we know sodium chloride reacts in aqueous solution to GIVE TWO MOLES of PARTICLES per MOLE of solute...

#NaCl(s) stackrel(H_2O)rarrNa^+ + Cl^-#

And #DeltaT_"boiling point elevation"=k_bxxm_"molality"#

#=0.512*K*kg*mol^-1xx2xx((49.2*g)/(58.44*g*mol^-1))/(0.500*kg)=1.72*K#

And this is a boiling point elevation, and so the pasta pot will boil at #101.72# #""^@C#...

Is the reason we add salt to water to make the boiling point elevate or to make the pasta or veggies tasty?

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