Chemistry Multiple Choice Questions on “Solid State Magnetic Properties”.
1. Which among the following compounds can show the properties of a Ferroelectric substance?
a) BaTiO3
b) PbZrO3
c) MnO2
d) CrO2
Answer: a
Clarification: At the Curie temperature (around 120 ºC) paraelectric BaTiO3 transforms into a ferroelectric structure. Ferroelectricity is the characteristic of certain substances that possess a spontaneous electric field which can be reversed by applying an external electric field.
2. All Ferroelectrics are pyroelectrics.
a) True
b) False
Answer: a
Clarification: Pyroelectricity is the ability of certain materials to generate a temporary potential difference when heated or cooled. Ferroelectrics form a subset of Pyroelectrics. Hence, all Ferroelectrics are Pyroelectrics.
3. All Ferroelectrics are piezo electrics.
a) True
b) False
Answer: a
Clarification: Piezoelectrics are substances whose polarization changes under the influence of stress. Ferro electric substances are considered as Piezoelectric since their polarization can change under the influence of an electric field.
4. Which among the following compounds is Antiferroelectric?
a) NiO
b) V2O3
c) PbZrO3
d) Fe3O4
Answer: c
Clarification: In the given list: NiO and V2O3 are antiferromagnetic substances, Fe3O4 is Ferrimagnetic and PbZrO3 is antiferroelectric. Antiferroelectric materials are those materials having ions which can polarize without external field (spontaneous polarization).
5. Which among the following statements is correct?
a) NaCl is a paramagnetic substance
b) Paramagnetic substances behave like an insulator
c) Cobalt is an Antiferromagnetic substance
d) On heating, ferrimagnetic substanceslose ferrimagnetism
Answer: d
Clarification: On heating, ferrimagnetic substances become paramagnetic and hence, lose their ferromagnetism. NaCl is diamagnetic in nature. Cobalt is a ferromagnetic substance.
6. What is the correct order of magnetic strength among the following elements?
a) Fe > Co > Ni > Cu
b) Fe > Ni > Co > Cu
c) Cu > Ni > Co > Fe
d) Cu > Fe > Ni > Co
Answer: a
Clarification: Magnetic strength depends on the number of unpaired electrons possessed by the element. Iron, Cobalt, Nickel and Copper have 4, 3, 2 and 1unpaired electron respectively. Hence, the correct order of magnetic strength is: Fe > Co > Ni > Cu.
7. Which of the following elements have a negative value of magnetic susceptibility?
a) Iron
b) Oxygen
c) Aluminium
d) Nitrogen
Answer: d
Clarification: Only Diamagnetic substances show a negative value of magnetic susceptibility. In the given list: oxygen and aluminium are paramagnetic, iron is ferromagnetic and nitrogen is diamagnetic. Therefore, Nitrogen has a negative value of magnetic susceptibility.
8. Which of the following is not Anti-ferromagnetic?
a) MnO
b) Mn2O3
c) MnO2
d) Mn
Answer: d
Clarification: MnO, Mn2O3, and MnO2 are Anti-ferromagnetic. Mn is paramagnetic in nature. Paramagnetism is when a substance is weakly attracted to a magnetic field.
9. In which of the following magnetic properties of elements does the magnetic susceptibility increase on increasing the temperature?
a) Paramagnetism
b) Anti-ferromagnetism
c) Ferromagnetism
d) Diamagnetism
Answer: b
Clarification: On increasing the temperature, the magnetic susceptibility of diamagnetic substances do not change, that of paramagnetic and ferromagnetic substances decrease and that of antiferromagnetic substances increase.
10. What is the temperature, above which a ferromagnetic substance shows no ferromagnetism called?
a) Curie temperature
b) Néel temperature
c) Critical temperature
d) There exists no such temperature
Answer: a
Clarification: The Néel temperature or magnetic ordering temperature is the temperature above which an antiferromagnetic material becomes paramagnetic. The Critical temperature of a gas is the temperature above which it cannot be liquefied by pressure alone. The temperature above which a ferromagnetic substance shows no ferromagnetism is called Curie temperature.