Answer:
It is calcium phosphide.
Explanation:
Calcium phosphide is a salt like material that is composed of calcium and phosphorus in the ratio of 2:5. It has the appearance of red brown Crystalline salt.
It is use as rodenticide to kill rats.
It is also use in fire works.
 
        
                    
             
        
        
        
Single replacement reactions.  For example copper is more reactive than silver.  So a copper wire in a silver solution will cause the silver to become a metal again.
        
                    
             
        
        
        
The question ask to predict the effect where as coal can be used to generate hydrogen gas by this endothermic reason and the best answer among your choices based on the element you give is letter C. raising the temperature of the reaction mixture. I hope my answer is correct
        
             
        
        
        
Answer:
The expression of an equilibrium constant will given as:
![K_c=\frac{[NH_3]^2}{[N_2][H_2]^3}](https://tex.z-dn.net/?f=K_c%3D%5Cfrac%7B%5BNH_3%5D%5E2%7D%7B%5BN_2%5D%5BH_2%5D%5E3%7D)
Explanation:
Equilibrium constant is defined as the ratio of concentration of products to the concentration of reactants each raised to the power their stoichiometric ratios. It is expressed as 
K is the constant of a certain reaction when it is in equilibrium

The expression of an equilibrium constant will given as:
![K_c=\frac{[NH_3]^2}{[N_2][H_2]^3}](https://tex.z-dn.net/?f=K_c%3D%5Cfrac%7B%5BNH_3%5D%5E2%7D%7B%5BN_2%5D%5BH_2%5D%5E3%7D)