आयोडीन घड़ी अभिक्रिया

एक समयबद्ध अभिक्रिया जो एक अनुमानित देरी के बाद अचानक गहरे नीले रंग की हो जाती है

Classroom Demonstrations Intermediate (High School) 45 मिनट ~$10.00

उद्देश्य

आयोडीन घड़ी अभिक्रिया का उपयोग करके अभिक्रिया गतिकी और अभिक्रिया दर पर सांद्रता और तापमान के प्रभाव का प्रदर्शन करें।

पृष्ठभूमि

The iodine clock reaction is a classic demonstration of chemical kinetics. Two colorless solutions are mixed and after a predictable delay, the solution suddenly turns dark blue. The delay occurs because bisulfite (HSO₃⁻) rapidly reduces any I₂ produced back to I⁻ (the clock mechanism). When all the bisulfite is consumed, I₂ accumulates and reacts with starch to produce the dramatic blue-black color. By varying concentration or temperature, students can explore factors affecting reaction rate.

सुरक्षा चेतावनियाँ

  • H₂SO₄ is corrosive
  • NaHSO₃ releases SO₂ gas if over-acidified — work in ventilated area
  • KIO₃ is an oxidizer
  • Hot plate surfaces are a burn hazard

आवश्यक PPE

goggles gloves lab_coat

सामग्री

  • Potassium iodate (KIO₃) (2 g)
    Solution A
  • Sodium bisulfite (NaHSO₃) (1 g)
    Solution B
  • Starch solution (1%) (10 mL)
    Indicator in Solution B
  • Sulfuric acid (0.5M H₂SO₄) (20 mL)
    Solution A acidification
  • Distilled water (500 mL)

उपकरण

Beakers (250 mL, 4) Magnetic stirrer Stopwatch Thermometer Graduated cylinders Hot plate Ice bath

प्रक्रिया

1

Prepare Solution A: Dissolve 2 g KIO₃ in 200 mL water, add 20 mL of 0.5M H₂SO₄.

5 मिनट
2

Prepare Solution B: Dissolve 1 g NaHSO₃ in 200 mL water, add 10 mL of 1% starch solution.

5 मिनट
3

Trial 1 (baseline): Mix 50 mL of A with 50 mL of B and start the stopwatch immediately. Record the time until the solution turns blue.

5 मिनट
4

Trial 2 (concentration effect): Mix 25 mL of A + 25 mL water with 50 mL of B. Record the time. It should take approximately twice as long.

7 मिनट
5

Trial 3 (temperature effect): Warm both solutions to 40°C. Mix 50 mL of each and record the time. It should be significantly shorter.

8 मिनट Handle warm solutions carefully
6

Trial 4 (cold): Cool both solutions to 10°C in an ice bath. Mix and record the time.

8 मिनट
7

Plot reaction time vs. concentration and temperature. Discuss rate law, activation energy, and the Arrhenius equation.

7 मिनट

अपेक्षित परिणाम

The blue color appears suddenly after a delay of 5–60 seconds depending on conditions. Doubling concentration roughly halves the time. Increasing temperature by 10°C roughly halves the time (consistent with the Arrhenius equation).

सफाई

Pour reacted solutions down the drain with water. Rinse all glassware. Clean the magnetic stirrer.

विवरण

श्रेणी
Classroom Demonstrations
कठिनाई
Intermediate (High School)
अवधि
45 मिनट
अनुमानित लागत
$10.00
चरण
7
सामग्री
5

अधिक प्रयोग

गायब होता बीकर (अपवर्तनांक मिलान) 15 min गैर-न्यूटोनियन तरल: ऊब्लेक 20 min घनत्व स्तंभ इंद्रधनुष 30 min तात्कालिक ठंड: अतिशीतित जल 120 min थर्माइट अभिक्रिया 30 min दोलनशील ब्रिग्स-राउशर अभिक्रिया 40 min ल्यूमिनॉल के साथ केमिल्यूमिनेसेंस 30 min सूखी बर्फ में मैग्नीशियम जलाना 25 min सोडियम और पानी की अभिक्रिया 25 min हाथी टूथपेस्ट 20 min

Frequently Asked Questions

What is the objective of आयोडीन घड़ी अभिक्रिया?
आयोडीन घड़ी अभिक्रिया का उपयोग करके अभिक्रिया गतिकी और अभिक्रिया दर पर सांद्रता और तापमान के प्रभाव का प्रदर्शन करें।
How difficult is आयोडीन घड़ी अभिक्रिया?
This experiment is rated as Intermediate (High School). It takes approximately 45 minutes to complete.
What safety precautions are needed for आयोडीन घड़ी अभिक्रिया?
Key safety precautions include: H₂SO₄ is corrosive; NaHSO₃ releases SO₂ gas if over-acidified — work in ventilated area; KIO₃ is an oxidizer.
What materials are needed for आयोडीन घड़ी अभिक्रिया?
The main materials required are: Potassium iodate (KIO₃), Sodium bisulfite (NaHSO₃), Starch solution (1%), Sulfuric acid (0.5M H₂SO₄), Distilled water.
What results should I expect from आयोडीन घड़ी अभिक्रिया?
The blue color appears suddenly after a delay of 5–60 seconds depending on conditions. Doubling concentration roughly halves the time. Increasing temperature by 10°C roughly halves the time (consistent with the Arrhenius equation).