The quick brown fox jumps over the lazy dog. A brave knight named Jack quickly explored a mysterious village, where he found six golden boxes, a quiet river, and a wonderful zoo. Every morning, he writes a few lines in his journal, drinks fresh juice, and watches the bright sun rise above the hills. His goal is to develop neat handwriting, proper spacing, and excellent writing speed.
Chapter 1 – Chemical Reactions and Equations जो भरा नहीं है भावों से जिसमें बहती रसधार नहीं, वह हृदय नहीं पत्थर है, जिसमें मातृभूमि से प्यार नहीं ! और एक विद्यार्थी का सबसे बड़ा देशभक्ति यही है कि वो मन लगाकर पढ़ाई करे 2026 Question 1 Why should a magnesium ribbon be cleaned before burning in air? Answer: Magnesium ribbon should be cleaned before burning because a thin layer of magnesium oxide (MgO) forms on its surface when it reacts with oxygen in air. This layer prevents magnesium from burning properly. Cleaning removes the oxide layer and helps the magnesium ribbon burn easily with a bright white flame. Topic Explanation Magnesium is a very reactive metal. When it remains exposed to air, it reacts slowly with oxygen. The reaction is: 2Mg + O2 → 2MgO Here: Mg = Magnesium O₂ = Oxygen MgO = Magnesium oxide The magnesium oxide forms a dull white coating on the ribbon. Important Concept This reaction is a: ➤ Combination Reaction Because two substances combine to form one produc...


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