Q. 54.2( 18 Votes )
What is a Universal indicator, Give one example?
Universal indicator is a homogenous mixture which is prepared by mixing some common indicators. It has pH ranging from 1-14 to indicate acidity or alkalinity of solutions.
Example: pH scale is a universal indicator. If we put a pH paper in lemon solution, then the reddish color of the paper turns “yellow” as shown in the picture below.
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i. Give an example for a combination reaction which is exothermic.
ii. Identify the oxidising agent, reducing agent in the following reaction:
H2S + Cl2⇒ 2HCl + S
iii. Name the phenomenon due to which the taste and smell of oily food changes when kept for a long time in open. Suggest one method to prevent it.Xam idea - Science
In one of the industrial processes used for manufacture of sodium hydroxide, a gas X is formed as by-product. The gas X reacts with lime water to give a compound Y which is used as a bleaching agent in chemical industry. Identify X and Y giving the chemical equation of the reactions involved.Xam idea - Science
(a) What are X, Y and Z?
(b) Write a balanced chemical equation of the reaction which takes place when X and Y combine to form Z. Indicate the conditions under which the reaction occurs.Lakhmir Singh & Manjit Kaur - Chemistry
Write the balanced chemical equations for the following reactions.
a. Sodium carbonate on reaction with hydrochloric acid in equal molar concentrations gives sodium chloride and sodium hydrogen carbonate.
b. Sodium hydrogen carbonate on reaction with hydrochloric acid gives sodium chloride, water and liberates carbon dioxide.
c. Copper sulphate on treatment with potassium iodide precipitates cuprous iodide (Cu2I2), liberates iodine gas and also forms potassium sulphate.Xam idea - Science
(a) What could metal X be?
(b) What is powder Y?
(c) With which substance metal X combines to form powder Y?
(d) What is substance Z? Name one domestic use of substance Z.
(e) Write a balanced chemical equation of the reaction which takes place when metal X burns in air to form powder Y.Lakhmir Singh & Manjit Kaur - Chemistry