Answer:
To balance a reaction, the amount of reactants must be equal to the amount of products, as stated by the Law of Conservation of Matter. It may help you to keep track of  the number of each element in a list as you try to balance. It's not able to be balanced.
 
        
                    
             
        
        
        
The Correct Answer is Eletric Current I think
        
             
        
        
        
Answer:
2) Add a solution of NaBr
Explanation:
Lead (II) bromide is an inorganic powdery substance that has a solubility in water of 0.973 g/100 mL at 20°C. It is insoluble in alcohol but is soluble in alkali, ammonia, NaBr, and KBr
PbBr₂ is slightly soluble in ammonia, and it reacts with NaOH to produce Pb(OH)₂ and NaBr
Therefore, the best solution for dissolving PbBr₂(s) is NaBr
 
        
             
        
        
        
Molar mass KCl = 74.55 g/mol
Number of moles:
mass KC / molar mass
149 / 74.55 => 1.998 moles 
Volume in liters: 500 mL / 1000 => 0.5 L 
Therefore:
M = moles / volume
M = 1.998 / 0.5
M = 3.996 mol/L⁻¹