Smita was working in a garage with the doors closed and automobiles engine running. After some time she felt breathless and fainted. What could be the reason? How can she be treated?

While working with the car engine in a closed garage Johan suddenly felt dizzy and fainted. What is the possible reason?

Veena observes that during winter setting of milk into curd takes more time while during summer, the same process happens faster. She asks about this difference in time taken to her elder sister. She also asks her sister about why certain reactions occur rapidly while others occur slowly. Her sister explains her about the various factors that affect the rate of chemical reactions. Based on the above scenario, answer the following questions. The reaction of aluminum metal with dilute hydrochloric acid takes place faster as compared to zinc metal. What could be the reason for this difference?

Write the given information as an equation and find its solution : Sakshl prepared some jam at home and filled it in bottles. After giving away 7 of the bottles to her friends she still has 12 for herself. How many bottles had she made in all ? If she filled 250 g of jam in each bottle, what was the total weight of the jam she prepared ?