A solid element is specific heat `1 Jg^(-1)K^(-1)`. If equivalent weight of an element is`9`, find its valence.

Answer

3

Explanation

According to Dulong and Ptit's law
At. wt. `xx "specific heat" = 6.4 cal g^(-1)`
`because` Specific heat `= 1J g^(-1) K^(-1) =(1)/(4.184) cal g^(-1) K^(-1)`
`:.` Valency `= ("At.wt.")/("Eq.wt.") = (6.4 xx 4.184)/(9) ~~ 3`
(`because` at.wt. `= (6.4)/(1//4.184))`