Question

1. Answer the following questions about Reaction F:
   1. Write the overall chemical equation for this reaction.

2. Calculate the number of drops theoretically required to change the color of the solution (change the solution from acidic to basic). Assume H₂SO₄ donates both its protons in this reaction. How does this compare with your data?

2. Answer the following questions about Reaction G:
   1. Write the overall chemical equation for this reaction. Identify the gas formed during this equation.

2. What color was the solution at the end the reaction? Which reactant was the limiting reactant? (Hint: no calculations are necessary! Just look at the color of the solution at the end.)

3. Calculate the molar concentration (in molarity) of the sodium ion, Na⁺, in the final solution.

3. Answer the following questions about Reaction H:
   1. Write the overall chemical equation for this reaction. Identify the gas formed during this equation.

b. Identify the reducing agent in this reaction.

Reaction	Observations
A: Pb(NO3)2 + KI	Powdery appearance, stuck to the walls of the test tube, solution has a yellow color
B/C: NiCl2 + AgNO3	Powdery white, percipate accumalted as pellets at the bottom
D: H2SO4 + Indicator	Yellow color when indicator added
E: NaOH + Indicator	Dark blue when indicator is added
F: H2SO4 + NaOH	Yellow with 10 drops, then after the 23rd drop turned blue
G: Na2CO3 + H2SO4	After 20 drops Na2CO3 dissolved, after two drops of indicator it turns a dark blue after 20 drops of H2SO4 a gas is produced and changes to yellow, adding more sulfuric acid didn’t produce more bubbles
H: Mg + H2SO4	Solid magnesium strip no longer visible

	B	C
Mass of empty test tube (g)	12.358g	7.675g
Drops of NiCl2	30	24
Drops of AgNO3	20	32
Conductivity of solution (μS/cm)	21,521 (μS/cm)	21,005 (μS/cm)
Mass of precipitate and test tube (g)	12.415 g	7.805 g

Answer 1

For the reaction F,

a) The balanced reaction is

b) H₂SO₄ is a dibasic acid, it furnishes two H⁺ ions per molecule in water. We requires twice the amount of NaOH of same concentration to change the colour of the solution (change the solution from acidic to basic).

For the reaction G,

a) The balanced reaction is

The gas released is carbon dioxide.

b) At the end of the reaction, solution is yellow in colour. It indicates that the solution is acidic. The limiting reagent here is Na₂CO₃ since it is the reactant which is completely used up during the reaction.

c) The product formed is Na₂SO₄. It is soluble in water and hence exist as Na⁺ and SO₄^2- ions.

Let n moles of Na⁺ is present in a solution of molality m and volume v before reaction. Then, the final solution will have the volume 2v (same volume of sulphuric acid is added to nuetralise the base)

molality = n/2v = m/2.

Therefore, molality of Na⁺ ions reduces to half in the final solution.

For the reaction H,

a) balanced reaction is

Gas released is H₂. Here Mg is oxidised and hence it is the reducing agent.