| 71. | The most reactive form of phosphorus is |
A. red phosphorus | |
B. yellow or white phosphorus | |
C. black phosphorus | |
D. purple phosphorus |
| 72. | Yellow phosphorus is kept safe |
A. in kerosene | |
B. in water | |
C. in petrol | |
D. In the air |
| 73. | Used in the manufacture of matchsticks – |
A. white phosphorus | |
B. red phosphorus | |
C. silicone | |
D. selenium |
| 74. | Bones and teeth contain about 50%- |
A. calcium phosphate | |
B. calcium silicate | |
C. calcium carbonate | |
D. calcium phosphate |
| 75. | Which of the forms of phosphorus shows the property of luminescence? |
A. white phosphorus | |
B. black phosphorus | |
C. red phosphorus | |
D. Sindoori Phosphorus |
| 76. | White phosphorus reacts with hot and concentrated solution of caustic soda to form – |
A. phosgene | |
B. phosphine | |
C. phosphoric acid | |
D. phosphorus pentoxide |
| 77. | The basic element of human bone is – |
A. calcium | |
B. phosphorus | |
C. iron | |
D. Zinc |
| 78. | The bone powder of birds is used as a fertilizer because it contains – |
A. from nitrogen | |
B. from phosphorus | |
C. from sodium | |
D. from potassium |
| 79. | Which of the following is attached to the end of the match stick? 1. Glue and glass powder 2. White phosphorus 3. Antimony trisulphide 4. Potassium chlorate Select the correct answer from the codes given below – |
A. 1,3 and 4 | |
B. 2,3 and 4 | |
C. 1, 2 and 3 | |
D. 1,2,3 and 4 |
| 80. | Which of the following is used to create a smoke screen in war? |
A. PH₃ | |
B. PH4 | |
C. PCI₃ | |
D. PCI₅ |