Ppt Rules

Question 1

What compounds are always soluble?

Answer 1

Salts of G1 elements

All nitrates

All ammonium salts

Question 2

Solubility of halides in compounds

Answer 2

Mostly soluble except SILVER and LEAD halides

Question 3

Solubility of sulfates

Answer 3

Mostly soluble except Ca, Ba, Pb sulfates

Question 4

Solubility of hydroxides and carbonates

Answer 4

Most INSOLUBLE, except G1 hydroxides and carbonates

Question 5

Solubility of metal oxides

Answer 5

Mostly insoluble

G1 and G2 react with water B

Question 6

Al3+ with NaOH and ammonia

Answer 6

White ppt for both
Soluble in excess for NaOH (forms complex salt)
Insoluble in excess for ammonia

Question 7

Ca2+ in NaOH and ammonia

Answer 7

NaOH: White ppt, insoluble in excess

No ppt or very slightly white ppt for ammonia

Question 8

Cu2+ in NaOH and ammonia

Answer 8

Light blue ppt
insoluble in excess for NaOH
soluble in excess for ammonia, dark blue colour

Question 9

Cr3+ in NaOH and ammonia

Answer 9

Grey green ppt for both

Soluble in excess in NaOH, green solution

Insoluble in excess for ammonia, partially dissolves on standing

Question 10

Fe2+ in NaOH And Ammonia

Answer 10

Grey green ppt
Insoluble in excess for both

Question 11

Fe3+ in NaOH and ammonia

Answer 11

Reddish brown ppt
Insoluble in excess for both

Question 12

Zn2+ in NaOH and ammonia

Answer 12

White ppt
Soluble in excess for both (forms complex salt w NaOH)