Team Texcellency – Texcellency

What will happen if a solution of sodium hydrocarbonate is heated? Give the equation of the reaction involved.

A: When a solution of Sodium Hydrocarbonate (NaHCO3), also known as Baking Soda, is heated: Decomposition Reaction: 2NaHCO3 → Na2CO3 + H2O + CO2 What happens: Sodium Hydrocarbonate breaks down into: Sodium Carbonate (Na2CO3) Water (H2O) Carbon Dioxide (CO2) Observations: Effervescence (bubbling) due to CO2 release Formation of a solid precipitate (Na2CO3) Practical Applications: Baking: […]

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Name the sodium compound which is used for softening hard water.

A: The sodium compound commonly used for softening hard water is Sodium Carbonate (Na2CO3), also known as Washing Soda. Sodium Carbonate removes calcium and magnesium ions, which cause water hardness, through a process called precipitation: Ca2+ + Na2CO3 → CaCO3 (precipitate) + 2Na+ Mg2+ + Na2CO3 → MgCO3 (precipitate) + 2Na+ This reaction forms insoluble

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Name the substance which on treatment with chlorine yields bleaching powder.

A: The substance that yields bleaching powder (CaOCl2) when treated with chlorine is Calcium Hydroxide (Ca(OH)2). Chemical Reaction: Ca(OH)2 + Cl2 → CaOCl2 + H2O This question belongs to the first chapter of the CBSE 10th Std Science book: Acids, Bases and Salts Buy the Book

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What is the common name of the compound CaOCl₂?

A: The common name of the compound CaOCl₂ is Bleaching Powder. Bleaching Powder, also known as Calcium Hypochlorite, is widely used: As a disinfectant and sanitizer in water treatment and swimming pools. As a bleaching agent in laundry and textile industries. To kill bacteria, viruses, and other microorganisms. In households, Bleaching Powder is often used

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Why should a magnesium ribbon be cleaned before burning in air?

A: When magnesium ribbon is stored, it reacts with the oxygen in the air and forms a thin layer of magnesium oxide on its surface. This oxide layer prevents the magnesium from burning properly. Cleaning the ribbon with sandpaper removes this layer, allowing the magnesium to react fully with oxygen and burn brightly. This question

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What does one mean by exothermic and endothermic reactions? Give examples.

A: Exothermic reactions release heat, like a warm campfire. Examples include burning wood or the reaction between baking soda and vinegar. Endothermic reactions absorb heat, making their surroundings cooler, like how an ice pack gets cold when you activate it. An example is when barium hydroxide mixes with ammonium thiocyanate. This question belongs to the

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Why is the amount of gas collected in one of the test tubes in Activity 1.7 double of the amount collected in the other? Name this gas.

The Magical Reaction: Remember our underwater adventure with the mug, electrodes, and bubbles? Well, it’s all about splitting water (H₂O) into its two best friends: hydrogen (H₂) and oxygen (O₂). The magical equation is: 2H2O→2H2+O2 For every two water molecules, we get one oxygen molecule and two hydrogen molecules. The Gas Mystery: The test tube

Why is the amount of gas collected in one of the test tubes in Activity 1.7 double of the amount collected in the other? Name this gas. Read More »

A solution of a substance ‘X’ is used for white washing. (i) Name the substance ‘X’ and write its formula. (ii) Write the reaction of the substance ‘X’ named in (i) above with water.

A: (i) The substance ‘X’ used for white washing is Quicklime or Calcium Oxide, and its chemical formula is CaO. (ii) When Calcium Oxide (CaO) reacts with water (H2O), it forms Calcium Hydroxide (Ca(OH)2). The reaction is as follows: CaO+H2O→Ca(OH)2 This is called the slaking of lime and the product, Calcium Hydroxide, is used for

A solution of a substance ‘X’ is used for white washing. (i) Name the substance ‘X’ and write its formula. (ii) Write the reaction of the substance ‘X’ named in (i) above with water. Read More »