All of the above. Halogens are extremely reactive. Their valency is -1 as they have 7 outer shell electrins and need 1 more to make it 8. They also react with metals to form salt. So the ans is (D)
Question 3 is uniformitarianism
Question 4 is sedimentary rock
Answer:
22.67 L of PH₃
Explanation:
The balanced equation is:

From the equation:

= 22.67 L of PH₃