[timzor]

I've tried doing some research for this but it dosen't make sense with the information given by the question.

"Write the chemical equation for preparation of sodium aluminate from hydrated alumina and caustic soda

Sodium Aluminate is manufactured in batches of around 100,000kg.
Final solution strength controlled to 19% Al₂O₃.
Desired caustic content is 25.5% NaOH.
Moisture content of Al(OH)₃ is about 10% free water.
Calculate the amount of:
kg of 50% NaOH
kg of Damp Hydrated alumina
kg of water
that is required to produce one batch "

The equation I managed to find was: Al(OH)₃ +NaOH --> NaAlO₂ +2H₂O 
Not sure if that equation is correct...

I don't see how the "Final solution strength controlled to 19% Al₂O₃. " can be related to the equation unless the alumina was converted into hydrated alumina. Is the caustic content specifying the strength of the final solution?

Any help is appreciated, thanks.