Q. Catenation is the ability of an atom to form bonds with other atoms of the same element. It is exhibited by both carbon and silicon. Compare the ability of catenation of the two elements. Give reasons.

Q. Where does the photosynthesis take place in plants?

Q. Identification: 1. Indian national Congress session: Calcutta (Sep 1920) Nagpur (Dec 1920) Madras (1927) Lahore (1929) 2. Important centers of Indian national movement (Non-cooperation Civil Disobedience Movement) (i) Champaran (Bihar) – movement of indigo planners (ii) Kheda (Gujrat) – Peasant Satyagraha (iii) Ahmedabad (Gujrat) – Cotton Mill Workers Satyagraha (iv) Amritsar (Punjab) – Jallianwala Bagh incident (v) Chauri Chaura (U.P) – calling of non-cooperation movement (vi) Dandi Gujarat Civil Disobedience.

Q. Give a brief description of the principles of distillation.

Q. Which acids are present in acid rain?

Q. Answer the following questions: Why does leather get hardened after tanning?

Q. On the basis of their electronic configurations, explain why alkali metals are highly reactive.

Q. What are convex polyhedrons?

Q. Define speedometer and odometer.

Q. What are normal elements?