Which method is used to extract essential oils from plants and flowers?
(a) Crystallization
(b) Sublimation
(c) Steam distillation
(d) Differential extraction
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The catalyst used in hydrogenation of oils is ………………..
Correct option is C) Ni
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In method of mixtures, why is it essential that density of solid sample be greater than the liquid in calorimeter?
1. In method of mixtures, solid sample gives away heat to liquid, and heat exchange between, solid, liquid and calorimeter is considered as isolated. 2. If density of solid sample is...
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(D) Write the answers of the following questions in about 50 words. (1) Discuss the importance of the following statement from the light of the extract of the novel 'The Sign of Four' - 'The trio - Holmes, Doctor Watson and Mary decide to visit Lyceum Theatre'. (2) Write in brief the theme of the given extract of the novel 'The Sign of Four'.
Mary comes to meet Sherlock with a case. For the past six years, an anonymous person has been sending a pearl to Mary on the same day each year. However,...
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Assertion (A) : Chromatography is used to separate the coloured pigments in flowers.
A) Both assertion (A) and reason (R) are correct and (R) is the correct explanation of (A).
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Vidhya and Vijay were studying the effect of certain radiations on flower plants. Vidhya exposed her plants to UV rays and Vijay exposed his plants
Frequency of UV rays is greater than infrared rays, hence UV rays are much more energetic than infrared rays. Plants cannot tolerate the exposure of high energy rays. As a...
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Describe the steps involved in balancing redox reactions by ion electron method (Half reaction method).
In this method two half equations are balanced separately and then added together to give balanced equation. Following steps are involved. Step 1: Write unbalanced equation for the redox reaction, assign...
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The method of removing individual plants or small groups of plants ………
D) Selective harvesting
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1. (a) Is ammonia more dense or less dense than air? (b) What property of ammonia is demonstrated by the Fountain Experiment? (c) Write the balanced equation for the reaction between ammonia and sulphuric acid. 2. Pick the odd member from the list giving reasons: (a) Ammonia, sulphur dioxide, hydrogen chloride, carbon dioxide. (b) Copper oxide, aluminium oxide, sodium oxide, magnesium oxide. 3. Give reasons for the following : (a) Liquid ammonia is used as a refrigerant in ice plants. (b) Aqueous solution of ammonia is used for removing grease stains from woollen clothes. (c) Aqueous solution of ammonia gives a pungent smell. (d) Aqueous solution of ammonia conducts electricity.
(1) (a) ammonia is less dense than air (b) solubility in water (c) 2NH3 + H2SO4 → (NH4)2SO4 (2) (a) Ammonia → because - NH3 is basic while, SO2,HCl and CO2 are acidic oxides. (b) CuO,...
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Organic pollutants include I. DDT II. HCl III. Pathogenic microorganisms IV. Oils The correct option is (a) I and IV (b) II and III
Answer is : (a) I and IV
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In advance countries like USA and UK the ………… method of measuring NI is popular. (a) Output Method / Product Method
Correct option: (2) only b
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