The compound which contains both ionic and covalent bonds is

In ${\mathrm{CH}}_4$ both Carbon and Hydrogen are non metallic elements. Hence, each C  H bond must be covalent nature. In ${\mathrm{C}}_2{\mathrm{H}}_2$ molecule, there are sigma and pie bonds present. As the electro negativity difference between Carbon and Hydrogen is very low (2.5 - 2.1= 0.4) the C - H bonds to be covalent. In KCN molecule both ionic and covalent bonds are present Ionic bond between K &CN  Covalent bond between C & N In KCl only ionic bond is present between K and Cl  ions