Group II

Question 1

Dilute NaOH and Cl2 at 70

Answer 1

3Cl2(g) + 6NaOH(aq) —> 5NaCl(aq)
+ NaClO3(aq) + 3H2O(l)
Cl=+5 in NaClO3

Question 2

Dilute NaOH and Cl2 at 15

Answer 2

Cl2(aq) + 2NaOH(aq) —> NaCl(aq)
+ NaClO(aq) + H2O(l)
Cl=+1 in NaClO

Question 3

Trend in IE energy

Answer 3

• Decrease down group
~ Increase shielding so larger distance between outermost e- and nucleus increase
~ Outweigh attraction to higher nuclear charge

Question 4

Trend in melting point

Answer 4

• Decrease down group
~ metallic
~ outer e get further from nucleus
~ less attraction between nucleus and bonding e-

• Anomaly in Mg lower than Ca

Question 5

Reactivity and reactivity with water & steam

Answer 5

• Increases down group
~ more shielding so outer e- easier to lose

• With water
M(s) + 2H2O(l) ->M(OH)2(s) + H2(g)
~Observation with water:
vigorous with steam, moderate, rapid, rapid
~X(OH)2(aq)->X^2+(aq)+2OH^-(aq)

• Steam:
~ X + H2O —> XO + H2
~ Reaction faster with steam as there’s extra energy
~ Mg bright white flame and white powder

Question 6

Solubility of hydroxides and equations

Answer 6

• Solubility increase down group
~ Mg(OH)2 not soluble
~ Ba(OH)2 most soluble

• X + 2H2O —> X(OH)2 + H2
• X(OH)2(aq)->X^2+(aq)+2OH^-(aq)

Question 7

Solubility of sulphate

Answer 7

• Solubility decreases down group
~ MgSO4 most soluble
~ BaSO4 least soluble

• Ba^2+ + SO4^2– —> BaSO4(s)

Question 8

Uses of G2: Ca, Mg(OH)2 & BaSO4

Answer 8

•Ca use in agriculture
~ CaO removes pollutants
~ Raise pH in soil

• Magnesium hydroxide
~ Indigestion, neutralises excess stomach acid

•Barium sulfate
~ not absorbed by blood
~ absorbs x ray so gut shows white on image

BaCl test for sulfate ions

Question 9

Extraction of Titanium

Answer 9

• Displacement

• TiCl4 + 2Mg —> 2MgCl2 + Ti

Question 10

Flue gas removal

Answer 10

CaO+2H2O+SO2 -> CaSO3+2H2O