Question

A student has taken a solid white powder from chemistry laboratory and added water to it. When she touched the beaker, she felt it became hot. She added more water to the beaker and took that solution in a test tube. Then she passed a gas trough the solution and found a white ppt in that test tube. She wants to identify the chemicals cand the chemical reactions involved.



Questions :
16. Which chemical she took initially in the beaker? a. Quick lime b. Slaked lime c. Lime water d. Calcium oxide
i. a and b
ii. b and c
iii. c and
d iv- a and d


17. Name the gas she used to get white precipitate. a. Hydrogen gas b. Oxygen gas c. Carbon dioxide d. Water vapour


18. When water is added to the white chemical the student took which type of chemical reaction has taken place? a. Exothermic reaction b. Combination reaction c. Decomposition reaction d. Endothermic reaction
i. a and b
ii. b and c
iii. c and d
iv. a , b and c


19. Precipitation reaction is a type of -----------reaction. a. Double displacement reaction b. Displacement reaction c. Redox reaction d. None of the above

20. What will happen to the white precipitate if excess amount of the gas is passed? a. The white colour will become more intense b. The white precipitate will disappear c. The white precipitate will settle down d. The amount of precipitate will reduce​

Answer 1

Answer:

a and b

b and c

c and d

a b and c