Formic acid is the simplest carboxylic acid, HCOOH. It is the cause of pain in bee and ant stings and nearly a million tonnes are made each year because it is a good preservative. In water, formic acid behaves as a weak acid:

HCOOH (aq) + H 2 O (l) ⇌ HCOO - (aq) + H 3 O + (aq)

The concentration of formate ions (HCOO - ) is increased by adding sodium formate (HCOONa). Which of the statements below is the best explanation of the process of returning to equilibrium after the sodium formate has been added?

Question

Formic acid is the simplest carboxylic acid, HCOOH. It is the cause of pain in bee and ant stings and nearly a million tonnes are made each year because it is a good preservative. In water, formic acid behaves as a weak acid: 
  
 HCOOH (aq)  + H 2 O (l)   ⇌   HCOO - (aq)  + H 3 O + (aq) 
   
 The concentration of formate ions (HCOO - ) is increased by adding sodium formate (HCOONa). Which of the statements below is the best explanation of the process of returning to equilibrium after the sodium formate has been added?

Answer

The H 3 O +  concentration will decrease, because some will react with HCOO -  to return to the equilibrium product/reactant ratio.

Answer

I don't know.

Answer

The HCOOH concentration will decrease, because it reacts with the added HCOONa.

Answer

The HCOO -  concentration will increase and concentration of the other species will decrease to balance the reaction.

Answer

The H 3 O +  concentration will increase, because the ratio of H 3 O +  to HCOO -  remains constant at equilibrium.

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Formic acid is the simplest carboxylic acid, HCOOH. It is the cause of pain in b...

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