Question

electrovalent compounds are hard but yet brittle?

Answer 1

In electrovalent compounds oppositely charged ions are arranged in particular manner. These oppositely charged ions are held together by strong electrostatic attraction force. For this strong attraction force electrovalent compounds are hard.
When force is applied to electrovalent compounds, deformation occurs and similar charged ions come closer, which cause repulsion between similar charged atoms which leads to the brittleness of electrovalent ions.