What is the molar mass of sodium hydroxide?

To calculate molar mass, go to the periodic table and find the masses of each atom present in sodium hydroxide. 
There's one oxygen, one hydrogen, and one sodium. 
The mass of sodium is: 22.99 
The mass of oxygen is: 16.00 
The mass of hydrogen is: 1.01 

add them together and you have your molar mass 
1(22.99) + 1(16.00) + 1(1.01)= 40.0 g/mol 

Hbr dissociates to form h+ and br-ca(oh)2 dissociates to form ca2+ and 2oh-the h+ and oh- react to form waterassuming the reactants are dissolved in water, the net reaction is h+ + oh- —> h2oif you’re asked to show all components of the reaction, the complete reaction is 2hbr + ca(oh)2 —> cabr2 + 2h2o