Find the pH of a 0.013 M solution of HF. (The valu...

Question

Find the pH of a 0.013 M solution of HF. (The value of Ka for HF is 3.5×104)

Jules Bruno · Accepted Answer

We’re being asked to calculate pH of a 0.013 M solution of HF.Since HA has a low Ka value, it’s a weak acid. Remember that weak acids partially dissociate in water and that acids donate H+ to the base (water in this case). The dissociation of HA is as follows:HF(aq) + H2O(l) ⇌ H3O+(aq) + F–(aq); Ka = 3.5×10-4[readmore]From this, we can construct an ICE table. Remember that liquids are ignored in the ICE table and Ka expression.The Ka expression for HA is:Ka=productsreactants=[H3O+][F-][HF]Note that each concentration is raised by the stoichiometric coefficient: [HA], [H3O+] and [A–] are raised to 1.Plugging in the equilibrium concentrations from the ICE table into the Ka expression:Ka=3.5×10-4=[H3O+][F-][HF]Ka=3.5×10-4=(x)(x)0.013-xThe equation simplifies to:3.5×10-4=x20.013Solving for x, the equilibrium concentration of [H3O+] and [F–]:x2=(3.5×10-4)(0.013)x2=4.55×10-10x = 2.13 × 10–5 MThis means [H3O+] = x = 2.13 × 10–5 M. We can now calculate for pH:pH = -log[H3O+]pH = -log[2.13×10-5]pH = 4.67The pH of 0.013 M HF solution is 4.67.

Problem: Find the pH of a 0.013 M solution of HF. (The value of Ka for HF is 3.5×104)

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Problem Details

Problem: Find the pH of a 0.013 M solution of HF. (The value of Ka for HF is 3.5×104)

FREE Expert Solution

Problem Details

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