Why The Charge Acquired By A Glass Rod When Rubbed With Silk Cloth Is Positive And The Charge Acquired By An Ebonite Rod When Rubbed With Woollen Cloth Is Negative?

In the case of glass rod, electrons are loosely bounded compared to silk cloth .hence it loses electrons &get positive charge.compared to ebonite rod, electrons are loosely bounded in woollen cloth.hence electrons are transferred from woollen cloth to ebonite rod & ebonite gets negative charge.