The correct answer is option 3. The IUPAC name is Iron(II) sulfide. It is the less stable amorphous form.  When this is powdered, it is pyrophoric or it ignites spontaneously in air. It readily reacts with hydrochloric acid producing hydrogen sulfide.
        
             
        
        
        
Answer:
0.1988 J/g°C
Explanation:
-Qmetal = Qwater
Q = mc∆T
Where;
Q = amount of heat
m = mass of substance
c = specific heat of substance
∆T = change in temperature
Hence;
-{mc∆T} of metal = {mc∆T} of water
From the information provided in this question, For water; m= 22.0g, ∆T = (24°C-19°C), c = 4.18J/g°C. 
For metal; m= 34.0g, ∆T = (24°C-92°C), c = ?
Note that, the final temperature of water and the metal = 24°C
-{34 × c × (24°C-92°C)} = 22 × 4.18 × (24°C-19°C)
-{34 × c × (-68°C)} = 459.8
-{34 × c × -68} = 459.8
-{-2312c} = 459.8
+2312c = 459.8
c = 459.8/2312
c = 0.1988
The specific heat capacity of the metal is 0.1988 J/g°C
 
        
             
        
        
        
It is highly reactive and when it is kept in open it does react with the oxygen present in the surroundings and burns therefore it is kept immersed in kerosene and please thank me and if you need more comment 
 
        
             
        
        
        
Answer:
pH = - log(0.000765) 
 = -(-3.11) 
 = 3.1
so the solution is basic
 rest you can check values using calculator