1got answers to 1-a)infrared b)X rays
4-a,c
plz try 2,3
1. what type of waves are used in:
a)photography in fog
b)detecting crystal structure
2.A solution of Na in liquid ammonia at -33°C conducts electricity.
On cooling the conductivity of this _______.
3.what are the reactions for extraction of metallic Ag from Argentite?
4.Multiple options correct:
Among these which species dont contain peroxide ions?
a)PbO2 b)H2O2 c)SrO2 d)BaO2
reply soon.will post more.
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16 Answers
1as discussed with arka ......
2. decreases....tho both did nt get concrete proofs to support da ans....or may b we r rite....
som1 plz......give da exp
21yes for 4th it should be a) only Sr is an alkaline earth metal and has peroxy linkages.
106ans 4.. shouldnt it be ab
as it asks.. peroxide ions... (i dont think that H2O2 has peroxide ions)
1peroxides...are formd by alkali and earth metals..only.....besides dis..1 can chek da the oxidation states of central of atom....Sr...has +4...which is not possible....hence it has peroxy..linkage........so ans shud..be (a) only
@asish...H2O2 ha speroxy ions
29@Avinav...H2O2 is not a superoxo compound...btw Asish meant that H2O2 will not dissociate in the solution to form 2H+ and O22- ions...but Asish i dont feel that we have to think this much...we just need to answer whether the compound has peroxy-linkage or not
106@govind: isnt peroxide linkage and peroxide ions altogether different things?
29@Asish..ofcourse they are different..
@Shankar SrO2 is a basic oxide and PbO2 is an amphoteric oxide..
1Ans for 3
Silver is extracted from the ore-argentite (Ag2S). The process of extraction of silver is called as cyanide process as sodium cyanide solution is used. The ore is crushed, concentrated and then treated with sodium cyanide solution. This reaction forms sodium argento cyanide.
process of extraction of silver
The solution of sodium argento cyanide combines with zinc dust and forms sodium tetra cyanozicate and precipitated silver. This precipitated silver is called spongy silver.
The spongy silver is fused with potassium nitrate to obtain pure silver. Then the silver obtained is purified by electrolytic process.
39Isn't this leaching? Selectively dissolving the metal(forming complex on its surface) when the impurities will not dissolve the same way.
1Thanks shankar.
knew the reactions but thought argentite to be an oxide ore
the names r so confusing!haematite=Fe2O3 but argentite=Ag2S[2]