When negatively charged colloids like ${\mathrm{As}}_2{\mathrm{S}}_3$ sol is added to positively charged $\mathrm{Fe}(\mathrm{OH}{)}_3$ sol in suitable amounts

When -vely charged colloid-like As_2​S₃​ sol is added to +vely charged Fe(OH)₃​ sol in suitable amounts both the sols are precipitated simultaneously it is due to the fact that negatively charged particles of the arsenious sulphide sol take up positive ions, resulting in neutralization of the charge on the colloidal particles and hence lowering the stability of the sol and both precipitate simultaneously. This is an example of mutual coagulation.

Hence, option 1 and 2 are correct statements.