Select the correct statement(s) regarding chemical reactions of Ln :

Hydroxides are definite compounds, not just hydrated oxides. When the metals are heated with carbon, the carbides ${\mathrm{Ln}}_3\mathrm{C},{ \mathrm{Ln}}_2{\mathrm{C}}_3$ and ${\mathrm{LnC}}_2$ are produced. They create halides by burning halogens in diluted acids to release hydrogen. Oxides ${\mathrm{M}}_2{\mathrm{O}}_3$ and hydroxides $\mathrm{M}{\left(\mathrm{OH}\right)}_3$ are produced.