Tag: chemistry

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Questions Related to chemistry

Multiple choice imperfections in solids solid state the solid state chemistry

Calculate the dencity of NaCl type ionic solid AB($M _{w}$=60) in $gm/CM^{3}$ if shortest distance between two nearest neighbours is 100 pm &solid having $20\%$ schottky defect$(N _{A}=6\times10^{23}$)

  1. 10

  2. 20

  3. 30

  4. 40
Reveal answer Fill a bubble to check yourself
D Correct answer
Multiple choice imperfections in solids solid state the solid state chemistry

When NaCl is doped with ${ 10 }^{ -3 }$ mole % of Sr${ Cl } _{ 2 }$, what is the number of cationic vacancies?

  1. ${ 10 }^{ -5 }\times { N } _{ A }$
  2. ${ 10 }^{ -7 }\times { N } _{ A }$
  3. 6.022$\times{ 10 }^{8 }{ N } _{ A }$

  4. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Multiple choice imperfections in solids solid state the solid state chemistry

The composition of a sample of iron oxide is $Fe _{0.93}O _{1.0}$. What percentage of iron is present in the form of Fe(III)?

  1. $5.053$
  2. $10.053$
  3. $15.053$

  4. None of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let the percentage amount of Fe(III) be x and the amount of Fe(II) be $1-x$. Hence,  
$3x+2(1-x) = 2/0.93 = 2.15053$
On solving, we get, $x = 0.15053$
So, % of Fe(III) = 15.053

Multiple choice imperfections in solids solid state the solid state chemistry

The defect observed in solid substances having low coordination number is

  1. Schottky

  2. Frenkel

  3. Vacancy

  4. All of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Frenkel defect is typically observed in ionic solids where there is a large difference in size between the cation and anion, leading to a low coordination number. In this defect, smaller ions (usually cations) leave their normal lattice sites and occupy interstitial sites. Schottky defect is found in ionic solids with high coordination numbers where ions of similar sizes are missing.

Multiple choice imperfections in solids solid state the solid state chemistry

If $100$ moles of NaCI are doped with ${10^{ - 3}}$ moles of $Sr{C _2}$ what is the concentration of cation vacancies?

  1. $6.02 \times {10^{18}}mo{l^{ - 1}}$
  2. $12.04 \times {10^{18}}mo{l^{ - 1}}$
  3. $3.01 \times {10^{18}}mo{l^{ - 1}}$
  4. $12.04 \times {10^{20}}mo{l^{ - 1}}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

10^-3 moles of SrCl2 in 100 moles of NaCl means 10^-5 moles of SrCl2 per mole of NaCl. This creates 10^-5 * 6.02 x 10^23 = 6.02 x 10^18 vacancies per mole.

Multiple choice imperfections in solids solid state the solid state chemistry

According to recent studies which of the following interstitial hydrides have simi-lattices that of their parent metals

  1. $La, Yb, W$
  2. $Yb, W, V$
  3. $V, I, a$
  4. $N, Pd, Ce, Ac$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

La, Yb, and W are known to form interstitial hydrides where the metal lattice remains essentially unchanged.

Multiple choice imperfections in solids solid state the solid state chemistry

Which of the following is an interstitial compound?

  1. $ PdCl _2 $
  2. $ NH _3 $
  3. $ZnO$
  4. $TiH$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

An interstitial compound is a compound that is formed when an atom with a small enough radius sits in an interstitial hole in a metal lattice.  examples of small atoms are boron, carbon and nitrogen.  these compounds play important role in industries. Examples: TiH, Fe3H and Mn4N

Multiple choice imperfections in solids solid state the solid state chemistry

Which of the following defects decrease the density?

  1. Interstitial defect

  2. Vacancy defect

  3. Frenkel defect

  4. Schottky defect
Reveal answer Fill a bubble to check yourself
B,D Correct answer
Explanation

Vacancy and Schottky defect which lead to decrease the density both are the types of a stoichiometric defect. In case of Frenkel defect and interstitial defect, there is no change in density of substance.

Multiple choice imperfections in solids solid state the solid state chemistry

Frenkel defect is also known as

  1. stoichiometric defect

  2. dislocation defect

  3. impurity defect

  4. non-stoichiometric defect
Reveal answer Fill a bubble to check yourself
A,B Correct answer
Explanation

(a, b) In Frenkel defect, dislocation of cations takes place and there is no change in stoichiometry of the crystal.

Multiple choice imperfections in solids solid state the solid state chemistry

Iron (II) oxide is written as $\overline{FeO}$. What does it mean?

  1. Fully pure

  2. Impure
  3. Ratio of $Fe$ and $O $ is 1:1

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Impurity defects are foreign atoms that replace some  of the atoms making up the solid or that squeeze into the interstices; they are important in the electrical behaviour of semiconductors, which are materials used in computer chips and other electronic devices.

An example of interstitial impurity  atoms is the carbon atoms that are added to iron to make steel.