University:
High School
Course:
High School Chemistry
Academic year:

2023
Views:

128

Pages:

2
Author:

Yasin N.

REACTIONS OF GROUP IV CATIONS1. Reactions of Zinc, Zn2+Zinc sulphide is precipitatedA white precipitate is obtained .1. To a little of the salt solution am-monium chloride and excess ofammonium hydroxide are addedand hydrogen sulphide is passedthrough it.Zinc hydroxide formed is soluble2. To a little of the salt solutionA white precipitate soluble inin excess of NaOH.NaOH solution is added drop byexcess of NaOH is formed.ZnSO4drop till in excess.Zn(OH)2 + 2NaOH-> Na,ZnO2+2H2O3. Ash test : About 2ml of the saltGreen colour is formed to theGreen ash is obtainedsolution is boiled with one or twoformation of double oxide ofdrops of conc.HNO, and a fewcobalt and zinc.drops of cobalt nitrate . A filterpaper dipped in it is burnt to ashes2. Reactions of Manganese , Mn2A pink or flesh coloured precipi-Manganese sulphide is pre-1. To a little of the salt solutionNH4C CI and excess of NH2OH aretatecipitated MnCl,+H,S-MnS+ 2HCI.added and H,S is passed throughit.Mn(OH)2 formed on exposure2. To a little of the salt solutionA white precipitate which turnsto air oxidised to Mn(OH)3 -NaOH solution is added drop bybrown on keepingMnCl2+2NaOH-Mn(OH)2+2NaCdrop till in excess4Mn(OH),+O,+2H,O-4Mn(OH),3. Permanganic acid test A little ofThis is due to the formation ofThe supernatent liquid gets athe salt is boiled with conc. HNO 3permanganic acidpink colourand a pinch of lead peroxide It is5PbO2 + 10HNO1 +2Mn2then diluted with water and allowed2HMnO,+10Pb(NO,)2to remain for a while.+2H,O+4H+ 3. Reactions of Cobalt ,Co2+1. To a little of the salt solution am-A black precipitateCobalt sulphide is precipitatedmonium chloride and ammonium.Co(NO)2 +H,Shydroxide are added and H2S isCoS + 2HnOpassed -2. To a little of the sallt solutionA reddish brown precipitate isCobalt ferricynaide is fromed .NH2OH 4 and pottassiumobtained.3CoCl2 + 2K,[Fe(CN),]ferricynaide solutions are added.Co3[Fe(CN),J2 + 6KCI4. Reactions of Nickel ,Ni21. To a little of the salt solutionA black precipitate. .Nickel sulphide is precipitatedNiCl+H2S NiS+2HCI.NH2C1 and excess NH OH areadded and H2S passed through it .2. To a little of the salt solution am-A rose red precipitateNickel dimethyl gloxime is pre-monium hydroxide and dimethylcipitatedgloxime are added.