What is the difference between a concentrated and a dilute acid?

1 Answer
Jun 8, 2017

Answer:

A concentrated acid is a species whose concentration is (typically) GREATER than #1*mol*L^-1#; whereas a...........

Explanation:

..........whereas a dilute acid is a species whose concentration is LESS than #1*mol*L^-1#. Note that this definition of acidity does not take into account whether protonolysis is complete or incomplete; i.e. #HF# and #HOAc# can BOTH be quite concentrated. Nevertheless, these are both quite weak Bronsted acids, i.e. the equilibrium......

#HX(aq)+H_2O(l)rightleftharpoonsH_3O^+ + X^-#

............lies somewhat to the left.

For sulfuric acid, the equilibrium lies to the right........

#H_2SO_4(aq) + 2H_2O(l) rarr 2H_3O^+ + SO_4^(2-)#

Given the definition advanced above, any solution of #H_2SO_4(aq)# whose concentration is LESS than #0.5*mol*L^-1# with respect to #H_2SO_4(aq)# would therefore be classified as a dilute acid. Why
#0.5*mol*L^-1# and not #1.0*mol*L^-1#. You should check your syllabus with regard to this definition; the cut-off point is arbitrary.

An important practical tip when you deal with conc. acids: when you dilute a strong acid with water IT IS ALWAYS ACID TO WATER, and NEVER WATER TO THE ACID. Why? Because if you spit in strong acid it will spit back.