TargetIIT

HELLO ALL. ANYONE PREPARING FOR IIT-JEE WOULD SURELY

GET HIS TOPICS DONE, BUT DURING THEIR PREPARATION,

MORE THAN MANY,NEGLECT A SUBJECT CALLED [b]

INORGANIC CHEMISTRY[/b]. THIS ALSO CREATES A

DIFFERENCE IN RANKS.TO,AVOID THAT FOR TIITIANS,THIS

THREAD IS STARTED. THIS THREAD WOULD CONTAIN AND

HOPEFULLY SOLVE A CONSIDERABLE NUMBER OF QUESTIONS

OF INORGANIC CHEMISTRY,BUT WELL WITHIN THE IIT-JEE

SYLLABUS.U CAN POST ANY OF UR INORGANIC DOUBT IN

THIS THREAD

1) IN TERMS OF POLAR CHARACTER, WHICH OF THE FOLLOWING ORDER IS CORRECT ?

A. NH[ss]3[/ss] < H[ss]2[/ss]O < HF < H[ss]2[/ss]S

B. H[ss]2[/ss]S <  NH[ss]3[/ss] < H[ss]2[/ss]O < HF

C. H[ss]2[/ss]O < NH[ss]3[/ss] < H[ss]2[/ss]S < HF

D. HF < H[ss]2[/ss]O < NH[ss]3[/ss] < H[ss]2[/ss]S

[hide]4)WHICH OF THE FOLLOWING HALIDES IS INERT TOWARDS HYDROLYSIS AT ROOM TEMPERATURE ?
A)SiCl[ss]4[/ss]
B)PCl[ss]3[/ss]
C)NCl[ss]3[/ss]
D)NF[ss]3[/ss] [/hide]

5)NUMBER OF S-S BOND IN H[ss]2[/ss]S[ss]n[/ss]O[ss]6[/ss]: ( NO OPTIONS REQUIRED )

[hide] 6)THE METALLIC LUSTRE EXHIBITED BY SODIUM IS EXPLAINED BY:

A)DIFFUSION OF Na[p]+[/p] IONS
B)OSCILLATION OF LOOSE ELECTRONS
C)EXCITATION OF FREE PROTONS
D)EXISTENCE OF BODY-CENTRED CUBIC LATTICE

[hide]7)WHICH OF THE FOLLOWING DOESN'T IMPART COLOUR TO THE FLAME ?
A)MgCl[ss]2[/ss]
B)SrCl[ss]2[/ss]
C)BaCl[ss]2[/ss]
D)LiCl

8)SALT A + S → B → WHITE PPT. A IS PARAMAGNETIC IN NATURE AND CONTAINS 55% K.THUS A IS:
A)K[ss]2[/ss]O
B)K[ss]2[/ss]O[ss]2[/ss]
C)KO[ss]2[/ss]
D)K[ss]2[/ss]SO[ss]4[/ss] [/hide]

9)THERMALLY MOST STABLE COMPOUND IS:
A)HOClO[ss]3[/ss]
B)HOClO[ss]2[/ss]
C)HOCl
D)HOClO

10) TO AN ACIDIFIED DICHROMATE SOLUTION,A PINCH OF Na[ss]2[/ss]O[ss]2[/ss] IS ADDED AND SHAKEN.WHAT'S OBSERVED ?
A) BLUE COLOUR
B) RED COLOUR CHANGING TO GREEN
C) COPIOUS EVOLUTION OF OXYGEN
D) BLUISH GREEN PRECIPITATE

11)Why bubbles are formed when H[ss]2[/ss]O[ss]2[/ss] is added with a few drops of blood ?

12)Will the strength of a standard solution of NaOH, be affected, when left in air for a few hours ?

13)What happens on hydrolysis of one mole of peroxodi-sulphuric acid ?

14)Oxalic acid(H[ss]2[/ss]C[ss]2[/ss]O[ss]4[/ss]) is sometimes used to clean rust stains from sinks and bathtubs.explain the cleaning action.

15) Why  'C' can't be used to reduce B[ss]2[/ss]O[ss]3[/ss] ?

16) Why MgCl[ss]2[/ss].6H[ss]2[/ss]O is heated with HCl to get anhydrous MgCl[ss]2[/ss] ?

17) What happens when sugar of lead is heated ?

18) What happens when NH[ss]3[/ss](g) reacts with Li metal ?

for 3rd ans is pcl4+ and pcl6-

for 2nd its  C

for ist may be b not sure

YES,VECTOR,U R RIGHT IN FIRST TWO POSTS. GIVE REASON FOR UR 3RD ONE

i m not sure fr ist q it cud be d
for fourth i think ans must be d

Q7. MgCl[ss]2[/ss]
Q1. b

Asish,did a basic mistake in Q.7. LiCl imparts crimson red colour to the flame.
and,ya u r right in Q.1,but please provide explanation

Ans 1)  b
2)    c
3)    d
4)    d
5)    n-1
6)    b
7)    d
8)    c

@aieee : Plz hide the qs answered or Bold them to avoid confusion :)

1)A

3) D

2) C

4) B

6)B (Even D is partially true)

9) A

10)B

Sure ones ---
2. C
3. D
4. D
6. B

1) ans. b is right
. 2) it's obviously c) ( which all of u hv done)
3) it hs become a common question. its rightly d).
4) also , right. d)
5) govind , u r right. but, cn u explain it ?
6) rightly b).
7) ans is a.
8) govind is right.
9) uttara, u r right. cn u say why ?
10) uttara , ur ans is not right.

[b]so, i'm hiding all the questions done. try the rest.[/b]

[hide]i hv provided new questions, requiring explanations. so, start answering ![hide]

19)[hide] A good salt analysis problem :[/hide]

A  +  heat  →   B (g)  +  C (l)

B is used as a propellant in ice-creams and reacts with NaNH[ss]2[/ss]  to form gas  D.

C  +   FeCl[ss]3[/ss]   →   yellow-brown lumps of a compound  E.

A   +   NOCl  →   an acidic salt  F   +   G ( a colourless solvent )

G  forms a mixture of two acids with water.

One of the acids decompose to give a reddish brown gas  and a gas H along with C.

Find  A  to  H.

@aieee
can u plz give some more hints for the above problem

Some points are pointing out "A" to be - NH[ss]4[/ss]NO[ss]3[/ss] ....ai4e plz confirm.

ya, avik . u r goin d right way. go on.

[1] Haven't got all of it though.

NH[ss]4[/ss]NO[ss]3[/ss] (A) ---Heat---> N[ss]2[/ss]O(B) + Paani (C)

(Nitrous oxide is used in ice creams n as a propellant.)

Paani + FeCl[ss]3[/ss] --------> Fe(OH)[ss]3[/ss] (E)

(F) shud be NH[ss]4[/ss]Cl, dunno whts (G), though the 2 acids it shud form with water shud be- HNO[ss]2 [/ss]& HN3 perhaps.

'Coz HNO[ss]2[/ss] will decompose to give Reddish brown NO[ss]2[/ss] gas.

Also, HNO[ss]2[/ss] + Water ----> HNO[ss]3[/ss] + NO gas.

well done. u got most of these. k.  A,B,C,E, F and one of the acids(HNO[ss]2[/ss]) along wid a gas, r right.

lets wait fr 1 more day. if no one answers the rest, i'll provide the answer.

2NaNH[ss]2[/ss] + N[ss]2[/ss]O → NaN[ss]3[/ss] + NaOH + NH[ss]3[/ss]
(source : Wikipedia)
G is N[ss]2[/ss]O[ss]4[/ss] ??

right govind. now its solved. summary :

A : NH4NO3     B :  N2O   C : water    D :  NH3    E : Fe(OH)3    F :  NH4Cl    G : N2O4   H : NO.


Some questions right here.

Q 20) Does GaCl[ss]2[/ss] exist ? Does Ga really show +2 oxidation state ?

Q 21) Whats lime softening ? ( related to Gr - II elements )

Q 22) Gr - I elements show which type of lattice structures ?

Q 23) What happens when bromide ions react with dichromate ions in acidic medium ?

Q 24) What cn be the best method to separate Cu[p]2+[/p] ions and Fe[p]2+[/p] ions ?

Q. no.. GaCl2 is actually Ga2Cl4 ≡ GaCl.GaCl3 .. +I and +III oxidation states

Ans 3...do u mean Grp 1..halides??..they exist in NaCl type of crystal..exception Cesium halides...

no , the metals in their solid states show which lattices.

ok u mean the kinda structures the metal form with themselves...that's BCC ...

Ans 4...Bromine ke case main oxidation hota hai unlike chromyl chromide...which happens in case of chlorine..

All  Gr - I elements show  BCC lattice except Li , which forms hexagonal closed packed structure.

so, 3 are answered . two remaining. Still m providing a salt analysis one. try it out.

Q 25) A  is a hygroscopic white solid , forms coloured bead with CuSO4  , with release of two gases  B  AND C.

A is reduced by Mg to form D and E. B is a self ionised gas , which when treated with K[ss]2[/ss]Cr[ss]2[/ss]O[ss]7[/ss] , turns it green due to formation of F.

B also turns starch iodate paper blue , due to liberation of gas G.

C on reaction with H forms C along with a colurless liquid.

Find A  to  H.

@Aieeee ..wat do u mean by the best method to seperate Cu[p]2+[/p] and Fe[p]2+[/p]..plz give some options if u can...btw i think K[ss]4[/ss][Fe(CN)[ss]6[/ss]] can help to distinguish them..but dunno if it's the best method or not...

And in that identification question that u posted..is there something to do with Borax bead test ?

@Asish...just adding something to ur answer....the compound is actually Ga[p]+[/p][Ga(Cl)[ss]4[/ss]][p]-[/p] ...

Cu[p]2+[/p] and Fe[p]2+[/p] salts can also be distinguished by adding NH[ss]4[/ss]OH solution to their aqueous solutions.Indeed,they can be separated as well as distinguished this way.
Cu[p]2+[/p] forms a soluble complex of tetramnine Copper(II) ions and a deep blue solution is obtained whereas for Fe[p]2+[/p] a green precipitate is formed which can be removed.
Distinction between these 2 can also be done by adding NaOH solution similarly,the only difference in this case being that for Cu[p]2+[p][/p][/p] a blue ppt is obtained.

For 12,i think the strength of NaOH will be affected as it will react with the acidic atmospheric gases like CO[ss]2[/ss],SO[ss]2[/ss] and oxides of Nitrogen etc[hide](given the amount of pollution these days!)[/hide]

hey it looks like i missed those questions...
btw ans 10 ...CrO[ss]5[/ss] will be formed..
blluuuue color liquid...so ans shud be A...

In Q.24) Actually , i hv seen this question at many places. the best way is to use Hydrogen sulphide in acidic medium , thus , Cu[p]2+[/p] is precipitated due to common ion effect.

Q.12) arka , gud logic , but u assumed too far. simple reason is the deliquescency of NaOH which would decrease its strength or concentration.

Q.25) Govind , u r goin right.   and Q.10) is right.

Ans 13
[image]44094011.jpg[/image]
Ans 16..it's dehydrated in the presence of HCl..coz otherwise it will form MgO..

ya surely thats the best reason for q 12,didnt come to my mind then.remembered the fact that bases like KOH are used as absorbers of acidic gases like CO[ss]2[/ss] etc.

r u sure that the ans for 7 is D aieee?
Li[p]+[/p] gives carmine colour on flame test.
i think it will be A Mg[p]2+[/p]
see this text taken from the link http://www.newton.dep.anl.gov/askasci/chem00/chem00614.htm :
Question -   Why is it that when magnesium is tested as a flame test
it is colourless not bright white?
------------------------------------------------
For an element to have a characteristic color in a flame test, it must have
an exited electronic state that emits radiation in the visible part of the
electromagnetic spectrum -- between about 400 and 700 nanometers. Magnesium
does not have an excited electronic state corresponding to these
wavelengths, so it emits no visible radiation.

tnx arka. actually ,i didn't see it, it ws a typo. and good explanation ! well done !
try answering the remaining ones.

21 ) This method is used for calcium hardness of carbonate form. Lime is added in equivalent amount to that of bicarbonate present and this result in the formation of insoluble calcium carbonate.

The solubility of CaCO3 at normal temperature is about 2Omg/l. The contact time in the tank is limited and usually a residual of about 40 mg/l CaCO3 results. Thus the softened water is saturated with CaCO3 which may deposit as a scale in the distribution system. This can be prevented by carbonation of CaCO3 which results in the formation of calcium bicarbonate


SOURCE : http://www.microbiologyprocedure.com/waste-water-microbiology/lime-softening.htm