- Organic Chemistry
- Aldehydes and Ketones
- Alkyl Halides, Alcohols and ethers
- Amines and other nitrogen compounds
- Aromatic Chemistry
- Carbohydrates, Amino acids, protein, Vitamin and Fat
- Carboxylic acids and its derivatives
- Chemistry in daily life
- General Mechanism in organic compounds
- Hydrocarbons
- Nomenclature and isomerism
24 - Solid State Questions Answers
IF D POSITn OF Na+ & Cl - rR INTERCHANGED IN NaCl having FCC ARRANGEMENT OF Cl- THEN IN D UNIT CELL OF NaCl
Na + WILL INCREASE BY 1 WHILE Cl- DECREASE BY 1
PLS TELL D REASON
No,
These will be no change by making this type of change
THE PYKNOMETRIC DENSITY OF NaClis 2.165X 10-3 wHILE ITS Xray density IS 2.178X103 kgm-3 the fraction of unoccupied sites in NaCl crystal is?ans) 5.96x 10-3. how we will caculate this fraction
Pyknometer is a device to measure density of substance. Density measured by pyknometer is called pyknometric density. In porous solids this density may be different from true density of solid if the liquid used is unable to fill the pores of solid.
I think that the first density will be 2.165 * 103
difference of density = 2178-2165 = 13 kg/m3
so fraction of unoccupied site = 13/2178 = 5.96 * 10-3
CRYSTALLINE SOLIDS HAVE
a) SHORT RANGE ORDER
b) ANISOTROPIC DISTRIBUTn
c) LONG RANGE ORDER
D) NO ORDER
AIIMS2001
SIR AS WE KNOW THAT BOTH THE OPTION B) & C) ARE CORRECT BUT IN THIS QUES WHICH OPTn WOULD BE MORE APPROPRIATE FOR CORRET ANS
.
According to me it should be b
for anisotropic character is a basic property of crystalline solids
Q In NAcL type str of A+ &B- ,2A ATOMS ARE REMOVED FROM EDGES &2B ATOMS ARE REMOVED FROM CORNER. FORMULA=? ANS =A14B15 . HOW?
In NaCl like structure B covers all the corners and face centre and A covers all the edge centres and body centre
Net contribution of B = 8*1/8 + 6*1/2 = 4
Net contribution of A = 12*1/4 + 1*1 = 4
now 2 A ATOMS ARE REMOVED FROM EDGES so remaining contribution = 10*1/4 + 1*1 = 7/2
and 2 B ATOMS ARE REMOVED FROM CORNE so remainnig contribution = 6*1/8 + 6*1/2 = 15/4
so formula will be A7/2B15/4 or A14B15