<span>NaCl is one and that is the only one that I know is for sure.
i hope this help!!!!!!!!!!</span>
        
             
        
        
        
X

H has a positive 1 charge. This means that having 3H = +3<span>.  This is a neutral compound so x= -3 because X+3H= 0
Y</span>

 is also neutral so 2X+Y= 0
we know X=-3 So, 2(-3)+Y=0
-6+y=0
Y=+6 charge 
Answer: The valency of X is -3. 
The valency of Y is 6
 
        
        
        
Answer:
mass = 508 g
Explanation:
Given data:
Number of moles of Cu = 8 mol
Mass in gram = ?
Solution:
Number of moles = mass/molar mass
Molar mass of Cu is 63.5 g/mol.
Now we will put the values in formula.
8 mol = mass /63.5 g/mol
mass = 63.5 g/mol
×8 mol 
mass = 508 g
 
        
             
        
        
        
Endothermic or C, if you would like a reason why, do not hestitate to ask