Three buffers are prepared using equal concentrations offormic acid (HCOOH) and sodium formate, hydrofluoric acid (HF) andsodium fluoride, and acetic acid (CH3COOH)and sodium acetate. Rank the three buffers from highest to lowest pH. According to the text, the Ka of the acids are as follows:
HCOOH: 1.77 × 10–4
HF: 6.8 × 10–4
CH3COOH: 1.76 × 10–5

solute : a solute is a substance that is dissolved in another substance is known as a solvent. it is mixed with a special mixture know as homogeneous mixture.

solvent: a solvent is a substance that dissolved a solute, which results in a solution is known as solvent.

answer: - first one is the correct answer. .

explanations: - potassium sulfide is and cobalt(ii) chloride is .

charge on k is +1, charge on s is -2, charge on co is +2 and charge on cl is -1.

in a double replacement reaction the ion exchange takes place. in general the reaction looks like:

if one of the product is insoluble as per solubility rules then a precipitate of it is formed.

when we mix the aqueous solutions of potassium sulfide and cobalt(ii) chloride then chloride ion goes with potassium ion and sulfide ion goes with cobalt ion and the balanced equation is written as:

k and cl has equal charges, similarly co and s has equal charges and hence no subscripts are used for the product side.

as per the solubility rules, cos is insoluble and so it's precipitate is formed.

looking at the given choices, first choice is correct.