Question

According to CRC’s, the melting point of cadmium bromide is 868$^{o}C$ . Which of the following equations best describes what occurs when cadmium bromide is heated to 868$^{o}C$ ?
A. $CdBr\left( s \right)\to CdBr\left( l \right)$
B. $CdB{{r}_{2}}\left( s \right)\to CdB{{r}_{2}}\left( l \right)$
C. $CdB{{r}_{2}}\left( s \right)\to Cd(s)+B{{r}_{2}}\left( g \right)$
D. $CdB{{r}_{2}}\left( s \right)\to C{{d}^{2+}}(aq)+2B{{r}^{-}}\left( aq \right)$

Answer 1

Hint: Melting point of a substance means at a certain temperature, the substance is going to change from one phase to another phase. Means at melting point one substance changes its phase from solid phase to liquid phase.

Complete step by step answer:
- In the question it is asked to find which of the given chemical equation suits when cadmium bromide is heated to 868$^{o}C$ .
- And also it is given that the melting point of cadmium bromide is 868$^{o}C$ .
- We know that at melting point only chemicals or substances change from one phase to another.
- Means cadmium bromide should change from one phase to another phase at 868$^{o}C$ .
- Generally at room temperature Cadmium bromide is in solid state.
- At 868$^{o}C$ cadmium bromide changes from solid state to liquid state.
- Means we have to choose an option where only changing of phase or state from solid to liquid is mentioned.
- The chemical formula of cadmium bromide is $CdB{{r}_{2}}$ .
- By observing all the options, option B only explains the changing of cadmium bromide from solid state to liquid state.
\[CdB{{r}_{2}}\left( s \right)\to CdB{{r}_{2}}\left( l \right)\]

So, the correct answer is “Option B”.

Note: Don’t be confused between melting point and boiling point. Both are not the same. At melting point a solid substance converts to liquid substance and at boiling point a liquid substance converts to gaseous substance.