Q. No.On addition of conc. to a chloride salt, colorless fumes are evolved but in case of iodide salt, violet fumes come out. This is because
1. reduces HI to
2. HI is of violet colour
3. HI gets oxidised to
4. HI changes to HI
In qualitative analysis when is passed through an aqueous solution of salt acidified with dil. HCl, a black precipitate is obtained. On boiling the precipitate with dil. , it forms a solution of blue colour. Addition of excess of aqueous solution of ammonia to this solution gives:
1. Deep blue precipitate of Cu(OH)2
2. Deep blue precipitate of [Cu(NH3)4]2+
3. Deep blue precipitate of Cu(NO3)2
4. Deep blue solution of Cu(OH)2 . Cu(NO3)2
In a cyclotrimetaphosphoric acid molecule, how many single and double bonds are present?
| 1. | 3 double bonds; 9 single bonds. |
| 2. | 6 double bonds; 6 single bonds |
| 3. | 3 double bonds; 12 single bunds |
| 4. | Zero double bonds; 12 single bonds |
Which of the following elements can be involved in pπ-dπ bonding?
1. Carbon
2. Nitrogen
3. Phosphorus
4. Boron
Affinity for hydrogen decreases in the group from fluorine to iodine. Which of the halogen acids should have highest bond dissociation enthalpy?
1. HF
2. HCl
3. HBr
4. HI
Bond dissociation enthalpy of E—H (£= element) bonds is given below. Which of the compounds will act as the strongest reducing agent?
|
Compound |
||||
|
389 |
322 |
297 |
255 |
On heating with concentrated NaOH solution in an inert atmosphere of white phosphorus gives a gas. Which of the following statement is incorrect about the gas?
| 1. | It is highly poisonous and has smell like rotten fish |
| 2. | Its solution in the water, decomposes in the presence of light |
| 3. | It is more basic than NH3 |
| 4. | It is less basic than NH3 |
Strong reducing behavior of is due to
1. Low oxidation state of phosphorus
2, Presence of two — OH groups and one P— H bond
3. Presence of one — OH group and two P— H bonds
4. High electron gain enthalpy of phosphorus
| Assertion (A): | SF6 cannot be hydrolysed but SF4 can be. |
| Reason (R): | Six F-atoms in SF6 prevent the attack of H2O on sulphur atom of SF6 |
| 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): | NaCl reacts with concentrated H2SO4 to give colourless fumes with a pungent smell. But on adding MnO2, the fumes become greenish-yellow |
| Reason (R): | MnO2 oxidizes HCl to chlorine gas which is greenish-yellow. |
| 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. |
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