Assertion (A): | In a particular point defect, an ionic solid is electrically neutral, even if few of its cations are missing from its unit cells. |
Reason (R): | In an ionic solid, Frenkel defect arises due to dislocation of cation from its lattice site to interstitial site, maintaining overall electrical neutrality. |
1. | (A) is false but (R) is true. |
2. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
3. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
4. | (A) is true but (R) is false. |
Assertion (A): | Due to metal deficiency defect, ZnO gives the appearance of yellow color |
Reason (R): | O2- ion occupies anion vacancy and forms F - center |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | Both (A) and (R) are false. |
Assertion (A): | Solids are rigid. |
Reason (R): | The constituent particles of solids cannot move from their positions. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | (A) is false but (R) is true. |
Select the correct option based on statements below:
Assertion (A): | Semiconductors are solids with conductivities in the range from 10-6 — 104 ohm-1 m-1. |
Reason (R): | Intermediate conductivity in semiconductors is due to a partially filled valence band. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | (A) is false but (R) is true. |
Select the correct option based on statements below:
Assertion (A): | The packing efficiency is maximum for the fcc structure. |
Reason (R): | The coordination number is 12 in fcc structure. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | (A) is false but (R) is true. |
Select the correct option based on statements below:
Assertion (A): | Total number of octahedral voids present in the unit cell of cubic close packing including the one that is present at the body center, is four. |
Reason (R): | Besides the body center there is one octahedral void present at the center of each of the six faces of the unit cell and each of which is shared between two adjacent unit cells. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | (A) is false but (R) is true. |
Select the correct option based on statements below:
Assertion (A): | Graphite is a good conductor of electricity. However, diamond belongs to the category of insulators. |
Reason (R): | Graphite is soft in nature whereas diamond is very hard and brittle. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | (A) is false but (R) is true. |
Assertion (A): | The total number of atoms present in a simple cubic unit cell is one. |
Reason (R): | Simple cubic unit cell has atoms at its corners, each of which is shared between eight adjacent unit cells. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | (A) is false but (R) is true. |
Select the correct option based on statements below:
Assertion (A): | The stability of a crystal is reflected by the magnitude of its melting point. |
Reason (R): | Greater the intermolecular forces of attraction, the higher will be the stability and melting point of the substance. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | Both (A) and (R) are false. |
Select the correct option based on statements below:
Assertion (A): | Due to Frenkel defect, the density of the crystalline solid decreases. |
Reason (R): | In Frenkel defect cation and anion leave the crystal. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | Both (A) and (R) are false. |