Metal Deficiency Defect

Q.

Analysis shows that nickel oxide has the formula $N{i}_{0.98}{O}_{{1.100}^{.}}$ What fraction of nickel exist as $N{i}^{2+}andN{i}^{3+}$ ions ?

Q.

A sample of ferrous oxide has actual formula $F{e}_{0.93}{O}_{1.00}$ In this sample, what fraction of metal ions are $F{e}^{2+}$ ions ? What type of non-stoichiometry defect is present in this sample?

Q.

FeO is found with a composition of $F{e}_{0.95}$O. It ranges from $F{e}_{0.93}$O to Fe_0.95O. Which type of defect is it showing here?

1. Stoichiometric

2. frenkel

3. Metal – excess

4. Metal-deficiency

Q. Which of the following statement(s) for crystals having Frenkel defect is/are correct?

1. Frenkel defects are observed where the difference in sizes of cations and anions is larger.
2. The density of crystals having Frenkel defect is lesser than that of a pure perfect crystal.
3. Usually alkali halides do not have Frenkel defect.
4. $AgBr$ crystal have both Frenkel defect and Schottky defect.

Q.

What type of stoichiometric defect is shown by $\mathrm{ZnS}$?

Q.

Which of the following is a non-stoichiometric defect?

1. Frenkel defect

2. Schottky defect

3. Interstitial defect

4. Metal deficiency defect

Q.

Match the types of defect given in Column I with the statement given in Column II.

$\begin{array}{cc}ColumnI& ColumnII\\ A.Impuritydefect& 1.NaClwithanionicsitescalledF-centres\\ B.Metalexcessdefect& 2.FeOwithF{e}^{3+}\\ C.Metaldeficiencydefect& 3.NaClwithS{r}^{2+}andsomecationicsitesvacant\end{array}$

Q. Analysis shows that FeO has a non-stoichiometric composition with formula $F{e}_{0.95}$O. Give reason.

Q.

FeO is found with a composition of $F{e}_{0.95}$O. It ranges from $F{e}_{0.93}$O to Fe_0.95O. Which type of defect is it showing here?

1. Stoichiometric

2. frenkel

3. Metal – excess

4. Metal-deficiency

Q. Which one of the following compounds show both Schottky and Frenkel defects?

1. $NaBr$
2. $AgBr$
3. $KBr$
4. $KCl$

Q.

When $NaCl$ is doped with $1.0\times {10}^{-3}$ mole of $SrC{l}_2$, the number of cation vacancy is ?

1. $6.023\times {10}^{18}$

2. $6.023\times {10}^{20}$

3. $2\times 6.023\times {10}^{20}$

4. $3.011\times {10}^{20}$

Q. Which of the following statements for crystals having Frenkel defect is correct?

1. Frenkel defects are observed where the difference in sizes of cations and anions is larger.
2. Usually alkali halides do not have Frenkel defect
3. $AgBr$ crystal have both Frenkel defect and Schottky defect
4. All of the above

Q.

Why is FeO(s) not formed is stoichiometric composition ?

Q. Doping of $AgCl$ crystal with $CdC{l}_2$ results in:

Q.

In metal deficiency defect

1. Anions are missing from the lattice points

2. Charge of the anion is increased

3. Charge of the anion is decreased

4. Cations are missing from the lattice points

Q.

The composition of a sample of Wustite is Fe0.93O1.0. What percentage of iron is present in the form of Fe(III) is

1. 15%

2. 20 %

3. 7%

4. 7.5%

Q. The analysis shows that nickel oxide has the formula ${Ni}_{0.98}O$. What fraction of the nickel exists as ${Ni}^{3+}$ ions?

1. $1$%
2. $2$%
3. $4$%
4. $8$%

Q.

FeO is found with a composition of $F{e}_{0.95}$O. It ranges from $F{e}_{0.93}$O to Fe_0.95O. Which type of defect is it showing here?

1. Stoichiometric

2. frenkel

3. Metal – excess

4. Metal-deficiency

Q. The correct statement regarding defect in crystalline solid is:

1. Frenkel defect change the density of solid
2. Frenkel defect is shown by ionic substance in which there is a small difference in size of ions
3. $AgBr$ shows both Frenkel and Schottky defect
4. Schottky defect does not changes the density of solid

Q. A transition metal M can exist in two oxidation state $+2$ and $+3$. It forms an oxide whose experimental formula is given by $M_{x}O$ where $x<1$. Then the ratio of metal ions in $+3$ state to those in $+2$ state in oxide is given by:

1. $\frac{1-x}{1+x}$
2. $1+2x$
3. $1+\frac{x}{2}$
4. $\frac{2(1-x)}{3x-2}$

Q. What type of defect is shown by $NaCl$ in
(a) stoichiometric defects, and
(b) non-stoichiometric defects?

Q. Find equivalent weight of underline elements in the following compounds:
(i) ${\underset{–}{Fe}}_2{O}_3$ (ii) $\underset{–}{Ca}O$
(iii) $H\underset{–}{Br}$ (iv) $\underset{–}{Fe}O$
(v) ${\underset{–}{Ag}}_{2}S$ (vi) ${\underset{–}{Al}}_2{O}_3$
(vii) $\underset{–}{Mg}C{l}_2$ (viii) $\underset{–}{Cu}O$
(ix) ${\underset{–}{Cu}}_{2}C{l}_2$ (x) $\underset{–}{Pb}O$
(xi) $\underset{–}{Pb}{O}_2$ (xii) ${\underset{–}{Pb}}_3{O}_4$
(xiii) $F{e}_3{O}_4$ (xiv) ${\underset{–}{PH}}_3$
(xv) ${\underset{–}{N}}_{3}H$ (xvi) ${\underset{–}{Fe}}_{0.93}O$
(xvii)${\underset{–}{Sn}}_{4.44}{O}_8$ (xviii) $\underset{–}{Ca}{H}_2$
(xix) ${\underset{–}{P}}_2{H}_4$ (xx) $\underset{–}{Sn}{O}_2$

Q. Question 15-16 is based on the following given information: A sample of ferrous oxide has actual formula $F{e}_{0.93}O$. What type of nonstoichiometric defect is present in this sample?

1. Impurity defect
2. Metal excess defect due to presence of extra cations at interstitial sites
3. Metal deficiency defect
4. Metal excess defect due to anionic vacancies

Q.

Example for an alkali metal is -------------

Q. Question 15-16 is based on the following given information: A sample of ferrous oxide has actual formula $F{e}_{0.93}O$. In this sample what fraction of metal ions are $F{e}^{2+}$ ions?

1. 0.93
2. 0.81
3. 0.79
4. 0.14

Q.

Which type of defect is shown by the following image?

1. Chemical impurity

2. Metal deficiency defect

3. Frenkel defect

4. Schottky defect

Q. (i) Write the electron-dot structures for Sodium, Oxygen, and Magnesium

Q. $Al{\left(OH\right)}_4^{-}$
If $M$ is the molecular weight and $E$ the equivalent weight , then :

1. $E=\frac{M}{4}$
2. $E=\frac{M}{3}$
3. $E=\frac{M}{2}$
4. none of these

Q. If the ionization potential of $Na$ is $495.8Kjmo{l}^{-1}$, the electron affinity of $CI$ is $349.4kJmo{l}^{-1}$ and lattice energy is $776kJmo{l}^{-1}$, the true statement for the formation of ionic bond in $NaCl$ is :

1. total energy released per mole of NaCl formed is $626kJ$
2. the ionic bond formed is unstable
3. the total energy absorbed per mole of $NaCl$ formed is $1125.4kJ$
4. net energy released in this process is $629.6J$

Q. Which has larger lattice energy among $ZnO$ and $NaCl$?

1. $ZnO$ > $NaCl$
2. $ZnO$ = $NaCl$
3. None of these
4. $ZnO$ < $NaCl$