D. C. Pant 💻

  कक्षा 10 विज्ञान: पाठ 2 - अम्ल, क्षारक एवं लवण के महत्वपूर्ण बहुविकल्पीय प्रश्न (MCQs) उत्तर सहित प्रश्न 1: निम्नलिखित में से कौन-सा एक अम्ल है? a) NaOH b) HCl c) KOH d) NH₃ उत्तर: b) HCl व्याख्या: HCl (हाइड्रोक्लोरिक एसिड) एक अम्ल है, जबकि NaOH और KOH क्षारक हैं। प्रश्न 2: निम्नलिखित में से कौन-सा पदार्थ अम्लीय प्रकृति को इंगित करता है? a) नीला लिटमस लाल हो जाता है। b) लाल लिटमस नीला हो जाता है। c) दोनों लिटमस अपरिवर्तित रहते हैं। d) कोई प्रतिक्रिया नहीं होती। उत्तर: a) नीला लिटमस लाल हो जाता है। व्याख्या: अम्ल नीले लिटमस को लाल में परिवर्तित करता है। प्रश्न 3: पीएच मान 7 से कम किसका संकेत करता है? a) क्षारक b) अम्ल c) लवण d) तटस्थ उत्तर: b) अम्ल व्याख्या: पीएच मान 7 से कम अम्लीयता को दर्शाता है। प्रश्न 4: चूने के पानी में कार्बन डाइऑक्साइड पास करने पर कौन-सा यौगिक बनता है? a) कैल्शियम ऑक्साइड b) कैल्शियम हाइड्रोक्साइड c) कैल्शियम कार्बोनेट d) कैल्शियम क्लोराइड उत्तर: c) कैल्शियम कार्बोनेट व्याख्या: Ca(OH)₂ + CO₂ → CaCO₃ + H₂O प्रश्न...

  Corrosion         It is the slow process of eating away metals by the reaction of atmospheric air and moisture, e.g. rusting of iron, formation of green coating over copper etc. PREVENTION OF CORROSION      Rusting of iron is prevented by galvanising, by making alloys, painting, greasing or oiling and tin-plating and chrome plating . Explained below -- 1. Galvanisation - It is the process of coating iron and steel object with a thin layer of zinc. It is done by dipping the object in molten zinc. The galvanised article is protected against rusting even if the zinc coating is broken. 2. Alloying - It is the method of improving the properties of a metal by mixing the metal with another metal or non-metal. 3. Alloying of iron - Pure iron is very soft and stretches easilywhen hot. It is mixed with a small amount of carbon and it becomes hard and strong. Iron is mixed with many metals to form different types of alloys. For example, when iron is mix...

  Types of chemical reaction The chemical reaction are classified into different classes depending upon the type of chemocal changes taking place. These reactions are as follows :   1.   Combination Reaction :-           A reaction in which two or more reactants combine to form a single product, is called combination reaction, e.g.   CaO (s) + H 2 O (l) → Ca(OH) 2(aq) + Heat   C (s) + O 2(g)     →    CO 2(g)   2.   Decomposition Reaction :-           A reaction in which a single reactants breaks down to form two or more products, is known as decomposition reaction. This reaction is opposite to combination reaction. e.g. CaCO 3(s)   →   CaO (s)   +   CO 2(g)   2AgCl (s)   →   2Ag (s) +   Cl 2(g)   2NaCl (l)   →   2Na (s)   +   Cl 2(g)   ...

  Balanced chemical equation             A balanced chemical equation is that in which the total number of atoms of each element are equal on both sides of the equation. The balancing of a chemical equation is based on law of conservation of mass. According to this – “mass can neither be created nor be destroyed during a chemical reaction.”               The method used for balancing chemical reaction is called hit and trial method as we make trials to balance the equation by using the smallest whole number coefficient. In this method the number of atoms of each element remains the same, before and after a chemical reaction.   BALANCING A CHEMICAL EQUATION             Several steps are involved in balancing a chemical equation. These steps are as follows :- Step (a) Writing unbalanced equation an...