Group 7 Reactions

Question 1

Explain the type of reaction that occurs between sodium chloride and sulfuric acid?

Answer 1

There is an acid base reaction
There is no REDOX reaction because Cl is a weak reducing agent
So the oxidation state of SO4 stays the same

Question 2

What do you observe from NaCl + H2SO4?

Answer 2

White steamy fumes

Question 3

Explain the type of reaction between sodium fluoride and sulfuric acid?

Answer 3

The reaction is the same as NaCl + H2SO4 because they are both weak reducing agents.

Question 4

What is the equation for NaCl/NaF + H2SO4?

Answer 4

NaCl/NaF(s) + H2SO4 (l) –> NaSO4 (s) + HCl/HF (g)

the oxidation state is unchanged

Question 5

Explain what type of reactions occur between NaBr + H2SO4 and list the equation?

Answer 5

• Acid Base: NaBr (s) + H2SO4 (l) –> NaSO4 (s) + HBr (g)
• Redox: H+ + Br- + H2SO4 –> SO2 (g) + 2H2O (l) + Br2 (l)

sulfur is reduced from +6 to +4

Question 6

What can be observed in the reaction between NaBr + H2SO4?

Answer 6

Fumes of HBr can be seen
These are brown in colour due to the production of Br2

Hbr from acid base, and Br2 from redox

Question 7

What type of reaction occurs between NaI + H2SO4, and list the equations?

Answer 7

• Acid Base: NaI (s) + H2SO4 (l) –> NaSO4 (s) + HI (g)
• Redox: 8H+ + 8I- (s) + H2SO4 (l) –> H2S + 4H2O (l) + 4I2 (l)

sulfur oxidises from +6 to -2

Question 8

What can be observed in the reaction of Nal + H2SO4?

Answer 8

HI - Steamy fumes
I2 - black, dark grey solid, this can vaporise causing purple gas
H2S - rotten egg smell

Question 9

Explain why a yellow solid may be observed prior to the I2 solid?

Answer 9

Sulfur is not reduced from +6 to -2 immediately, it becomes SO2, then S and this sulfur (0) is observed as temporary yellow solid