Reactivity of Alkali Metals

The video tutorial demonstrates the reactivity of alkali metals with water, starting with lithium and progressing to caesium. Each metal is placed under argon to prevent premature reactions with air. The experiment uses the same number of atoms for each metal to ensure consistency. Lithium reacts mildly, while sodium reacts vigorously, producing a yellow flame. Potassium's reaction is more intense, and rubidium produces a blue flame. Caesium, the most reactive, reacts rapidly. The video concludes with a discussion on the reactivity of these metals and highlights sodium as the most interesting reaction.

What is the main reason for using argon in the experiment setup?

• To increase the reaction rate

• To prevent the metal from reacting with air

• To cool down the metal

• To change the color of the flame

Why is the same number of atoms used for each metal in the experiment?

• To ensure a fair comparison of reactivity

• To reduce the cost of the experiment

• To make the experiment faster

• To prevent any reaction from occurring

What is observed when sodium reacts with water?

• It reacts quietly without any visible change

• It forms a blue flame

• It sinks to the bottom without reacting

• It catches fire and shows a yellow flame

What safety precaution is mentioned during the potassium reaction?

• Conducting the experiment outdoors

• Wearing protective gloves

• Adding a safety shield

• Using a larger quantity of water

What color is associated with the rubidium flame during its reaction with water?

• Yellow

• Blue

• Green

• Red

Why do rubidium and caesium sink in water?

• They are denser than water

• They are less reactive

• They are lighter than water

• They do not react with water

Which metal is described as the most reactive in the experiment?

• Potassium

• Sodium

• Lithium

• Caesium

What is the reason given for not experimenting with francium?

• It is too expensive

• It is too dangerous

• It is not reactive enough

• There is not much left

What is the narrator's favorite metal reaction and why?

• Caesium, because it is the most reactive

• Potassium, because it is the most colorful

• Sodium, because it builds up tension and heat

• Lithium, because it is the least reactive

What happens to the sodium when it is dropped into the tank at the end of the video?

• It sinks and does not react

• It dissolves without any reaction

• It reacts violently and disappears

• It floats and reacts slowly