Related InterviewSolutions

• “Coal is burnt”, “crackers are burnt” ………. changes Are they physical changes (or) chemical changes?
• 0.29 g of hydrocarbon when burnt completely in oxygen produces 448 ml of carbon dioxide at STP. From the information, calculate the i) mass of carbon dioxide formedii) mass of element carbon in carbon dioxide iii) mass of hydrogen in hydrocarbon.
• Give reasons for the following. 1) Why do we add salt to water during electrolysis of water? 2) Why does hydrogen gas put off the burning splinter and it burns with blue flame? 3) Why does carbon dioxide turn lime water milky?
• (a) A reaction in which two or more substances combine to form a single substance is called a................ reaction.(b) A.................. is a substance which changes the rate of a chemical reaction without undergoing a chemical change.(c) The formation of gas bubbles in a liquid during a reaction is called............... (d) The reaction between an acid and a base is called................... (e) Soluble bases are called..............(f) The chemical change involving iron and hydrochloric acid illustrates a..................reaction.(g) In the type of reaction called..................two compounds exchange their positive and negative radicals.................. respectively.(h) A catalyst either................. or................. the rate of a chemical change but itself remains.................... at the end of the reaction.(i) The chemical reaction between hydrogen and chlorine is a............... reaction(j) When a piece of copper is added to silver nitrate solution, it turns................ in color.
• Explain the following types of chemical reactions giving two examples for each of them.(a) combination reaction(b) decomposition reaction(c) displacement reaction(d) double decomposition reaction
• A substance X undergo a chemical change involving the loss of hydrogen and this result in the formation of a byproduct. What type of agents are X and Y? (Reducing agent or oxidizing agent).
• Explain any two characteristics of chemical reaction with experiment.
• What are chemical combination or synthesis reactions ? Chemical combination or synthesis:
• Why do the smell and taste of food items change?
• What are catalyst?