Question

Laboratory Instructor Name Date Lab Day Time Pre-lab 6 Analysis of Unknown Solutions Write a balanced equation for the reaction that occurs when an aqueous solution of iron(1I) chloride is mixed with an aqueous solution of potassium hydroxide. 1. a b. Write a net ionic equation for the above reaction. What simple test would you use to identify the possible presence of HCI(aq)? What result do you expect if the solution is HCI(aq)? 2. What preliminary test results are you looking for to identify conclusively your unknown solutions as Set B? Explain. 3. 4. A student had a set of solutions labeled A-E which contained, in no order, aqueous solutions of KOH, H,SO, Fe(NO), HBr, and Sr(NO) After the initial pH test they determined that A was a base, B/C were neutral, and D/E were acids. They then mixed B and C with D and then E and got a precipitate with the CD mixture but not the CE, BE or BD mixtures. What are the solution assignments?

Answer 1

1.

(a).

Balanced Chemical reaction is :

FeCl2 (aq) + 2 KOH (aq) ------------------------> Fe(OH)2 (s) + 2 KCl (aq)

Here,

# Strong electrolytes which are soluble in water are : FeCl₂ (aq), KOH (aq) and KCl (aq) ,They completely dissociated into their ions.

# Weak electrolytes which are insoluble in water is : Fe(OH)₂ (s) ,This will form green precipitates.

Therefore,

Complete ionic equation is :

Fe²⁺ (aq) + 2 Cl^- (aq) + 2 K⁺ (aq) + 2 OH^- (aq) ------------------------> Fe(OH)₂ (s) + 2 K⁺ (aq) + 2 Cl^- (aq)

The ions which appears both the sides in equations are known as spectators ions i.e. K⁺ and Cl^- ions and they are cancel out while writing net ionic equation.

(b).

Net ionic equation : Cancel the all spectators ions on both the sides of equation

Fe2+ (aq) + 2 OH- (aq) ------------------------> Fe(OH)2 (s)