An 8.65-g sample of an unknown group 2a metal hydroxide is dissolved in 85.0 ml of water. an acid-base indicator is added and the resulting solution is titrated with 2.50 m hcl(aq) solution. the indicator changes color signaling that the equivalence point has been reached after 56.9 ml of the hydrochloric acid solution has been added.

Answer;

The molar mass of metal hydroxide = 121.66 g/ mole

The formula is Sr(OH)2

Explanation;

M(OH)2 + 2 HCl = MCl2 + 2 H2O  

Moles of the acid = 2.5 x 56.9 / 1000 = 0.14225  

Therefore; moles of hydroxide at the eq point = 0.0711 moles  

These have a mass of 8.65g

Thus; mass of 1 mole = 8.65 / 0.0711

         = 121.66 g / mole  

That means the compound is Sr (OH)2 ..

it should have an internal chamber and two thermometers sticking out of the top. the internal chamber will also be closed off from the outside.