The formula equation for the reaction between hydroiodic acid and beryllium hydroxide is as below
Be(OH)2 + 2 HI = BeI2 + 2H2O
Formula of hydroiodic is = HI
formula of beryllium hydroxide = Be(OH)2
1 mole of Be(OH)2 react with 2 mole of HI to form 1 mole of BeI2 and 2 mole of H2O