2. Choose the correct alternative and rewrite the sentences.
1. When Hydrochloric acid is added on magnesium ribbon ---
-----gas is released
1. N2
ii. H2
iii. Co2
iv. 02
2. Resistance of two conductors 15 ohm and 45ohm connected in parallel combination is
i.11.25
ii. 0.1125
iii. 112.50
iv. 1.250
3. When universal indicator solution is added in pure water it changes to
colour
i Orange
ii. Violet
ii. Red
iv. Green
4. -------is a simple radicle.
i. CIO3
ii. No2
iii. No3
iv. Na
5.------is a natural indicator.
i. Phonoylepthalene
ii Litmus paper
iii Methyl orange
Answers
Answer:
Magnesium reacts with dilute hydrochloric acid in a conical flask which is connected to an inverted measuring cylinder in a trough of water. The volume of hydrogen gas produced is measured over a few minutes, and the results are used to plot a graph
This is intended as a class practical. It is best if the students work in pairs because setting up and starting the experiment requires more than one pair of hands. One student can add the magnesium ribbon to the acid and stopper the flask, while the other starts the stopclock. During the experiment, one student can take the readings while the other records them. The experiment itself takes only a few minutes. But allow at least 30 minutes to give students time to set up, take readings and draw graph.
Hydrogen gas (extremely flammable) is generated in the experiment. Students should not have access to any source of ignition.
Equipment
Apparatus
Eye protection
Conical flask (100 cm3)
Single-holed rubber bung and delivery tube to fit conical flask (note 1)
Trough or plastic washing-up bowl (note 2)
Measuring cylinders (100 cm3), x2
Clamp stand, boss and clamp
Stopwatch
Graph paper