Elements Of The Sea: Hydrogen Halides

Question 1

How do you produce hydrogen halides

Answer 1

Reacting sodium halide with sulphuric acid

Question 2

What product is formed when you react NaF with sulphuric acid

Answer 2

HF ( hydrogen fluoride )

Question 3

What product is formed when you react NaCl with sulphuric acid

Answer 3

HCl ( hydrogen chloride)

Question 4

What product is formed when you react NaBr with sulphuric acid

Answer 4

HBr

SO 2 and Br 2 = redox reaction

Question 5

What product is formed when you react NaI with sulphuric acid

Answer 5

HI

H2S ( rotten egg smell ) and I2 ( black solid ) = redox reaction

Question 6

What happens to thermal stability of hydrogen halides as you go down the group

Answer 6

Decreases ( opposite to group 2 = anomaly = normal rules don’t apply )

Question 7

What happens to average bond enthalpy of hydrogen halides as you go down the group

Answer 7

Decreases

Question 8

What does thermal stability of hydrogen halides decrease as you go dow the group

Answer 8

• bond enthalpy takes precedent over bond polarity

- H-I breaks first because of lower bond enthalpy

Question 9

What happens when hydrogen halides react with water and give equation for HCl

Answer 9

Hydrogen halides completely dissociate to form 100% acidic solution

H2O(l) + HCl(aq) —> H3O+(aq) + Cl-

Question 10

What is H3O+

Answer 10

Oxonium ion = dative bond

Question 11

What is the exception to the rule of hydrogen halides reacting with water to form 100% acidic solutions

Answer 11

HF ( hydrogen fluoride )

Question 12

What happens when hydrogen halides react with ammonia and give equation for HCl

Answer 12

All react to make salts

NH3(g) +HCl(g) —> NH4 Cl (s)

Question 13

What happens when hydrogen halides react with sulphuric acid

Answer 13

• HF & HCl = no reaction
• HBr = SO2
• HI = H2S