Alkali Metal Reactivity: Water, Chlorine, Oxygen, and Flame Tests

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Element	Observation	pH indicator
Lithium	Move slowly on the surface of the water. Emitted a negligible amount of white smoke The reaction produced a colourless solution.	10
Sodium	Move moderately on the surface of the water with ‘hiss’ sound. It burnt with yellow in colour. Emitted white smoke The reaction produced colourless solution	11
Potassium	Move enthusiastically on the surface of the water with ‘hiss’ and ‘pop’ sound It burnt with red in colour in colour. Emitted large amount of white smoke. The reaction produced colourless solution. Get to Know The Price Estimate For Your Paper Topic Deadline: 10 days left Number of pages Email Invalid email By clicking “Check Writers’ Offers”, you agree to our terms of service and privacy policy. We’ll occasionally send you promo and account related email "You must agree to out terms of services and privacy policy" Write my paper You won’t be charged yet! Don't use plagiarized sources. Get your custom paper on “ Alkali Metal Reactivity: Water, Chlorine, Oxygen, and Flame Tests ” Get high-quality paper NEW! smart matching with writer	12

Experiment 2: Reactivity with chlorine.

Alkali Metal	Observation
Lithium	Burnt slowly with the red flame Very heavy black soot are produced A white solid is produced
Sodium	Moderate time to burn out with the yellow flame Heavy black soot are produced A white solid is produced
Potassium	Take short time to burn out with purple flame White and black soot are produced A white solid is produced

Experiment 3: Reactivity with oxygen

Element	Observation	pH indicator
Lithium	Burn slowly with the red flame Emitted white smoke and the element changed its colour from grey to white in colour eventually. Get quality help now writer-Charlotte Verified writer Proficient in: Chemistry 4.7 (348) “ Amazing as always, gave her a week to finish a big assignment and came through way ahead of time. ” +84 relevant experts are online Hire writer When the white solid is mixed up with water, it’s produced colourless solution.	8
Sodium	Burnt moderately with the yellow flame. Emitted small amount of white smoke and the element changed its colour from white to black in colour. When the white solid is mixed up with water, it’s produced colourless solution.	11
Potassium	Burnt robustly until the element become slightly red flame in colour Emitted big amount of white smoke and the element changed from white to black colour When the white solid is mixed up with water, it’s produced colourless solution.	14

Experiment 4: Flame tests

Metal chloride + HCl	Observation
Lithium Chloride (LiCl)	Change the mix solution to green-yellowish Produced red flame
Sodium Chloride (NaCl)	Change the mix solution to yellowish Produced violet flame
Potassium Chloride (KCl)	Change the mix solution to green-yellowish Produced yellow flame

Experiment 1: Water Reactivity

Alkali metals exhibit a reaction with water, generating alkali solutions and liberating hydrogen gas. The chemical equations for this reaction are:

2Li(s)+2H2O(aq)→2LiOH(aq)+H2(g)

2Na(s)+2H2O(aq)→2NaOH(aq)+H2(g)

2K(s)+2H2O(aq)→2KOH(aq)+H2(g)

Observations show that as we move down the alkali metal group, reactivity increases. Testing LiOH, NaOH, and KOH with a pH indicator yields results above 7, indicating alkaline characteristics.

Experiment 2: Chlorine Reactivity

Alkali metals (Li, Na, K) react with chlorine gas, forming metal chlorides. The chemical equations are:

2Li(s)+Cl2(g)→2LiCl(s)

2Na(s)+Cl2(g)→2NaCl(s)

2K(s)+Cl2(g)→2KCl(s)

Scientifically, in this reaction, alkali metals donate one electron to chlorine atoms to achieve inert noble gas configurations.

Experiment 3: Oxygen Reactivity

Alkali metals (Li, Na, K) react with oxygen to produce white-colored metal oxides. The chemical equations are:

4Li(s)+O2(g)→2Li2O(s)

4Na(s)+O2(g)→2Na2O(s)

4K(s)+O2(g)→2K2O(s)

Observations suggest that reactivity increases down the alkali metal group. These metal oxides dissolve in water to form metal hydroxide solutions with pH readings above 7. The chemical equations are:

Li2O(s)+H2O→2LiOH(aq)

Na2O(s)+H2O→2NaOH(aq)

K2O(s)+H2O→2KOH(aq)

Experiment 4: Flame Test

Alkali metals exhibit distinct flame colors as follows:

Lithium: Red
Sodium: Yellow
Potassium: Blue

Scientifically, when alkali metals are introduced into a flame, they emit characteristic colors. This phenomenon occurs as alkali metal ions are reduced to gaseous metal atoms. These atoms absorb sufficient energy from the high-temperature flame, causing electrons in the valence electron shell to become excited to higher energy levels. As these electrons return to their ground state, they release energy in the form of visible light. The varied colors observed in alkali metals result from the emission of light at specific wavelengths, dictated by the valence electrons' transition from higher to lower energy subshells during the de-excitation process.