The table below shows the physical properties of four different substances: A\mathbf{A}A, B\mathbf{B}B, C\mathbf{C}C, and D\mathbf{D}D.
| Substance | Melting point (∘C^\circ\text{C}∘C) | Boiling point (∘C^\circ\text{C}∘C) | Soluble in water? | Conducts electricity in solid state? | Conducts electricity in molten state? |
|---|---|---|---|---|---|
| A\mathbf{A}A | 114114114 | 184184184 | No | No | No |
| B\mathbf{B}B | 770770770 | 142014201420 | Yes | No | Yes |
| C\mathbf{C}C | 171017101710 | 223022302230 | No | No | No |
| D\mathbf{D}D | 327327327 | 174917491749 | No | Yes | Yes |
Identify which substance is a liquid at a temperature of 150∘C150^\circ\text{C}150∘C.
Substance B\mathbf{B}B is an ionic compound. Use the data in the table to explain why.