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प्रश्न
Write true or false .
A black residue is formed when sugar is heated .
विकल्प
True
False
उत्तर
True
APPEARS IN
संबंधित प्रश्न
How would you show that setting of curd is a chemical change?
Name three biochemical catalysts found in the human body.
Complete and balance the following chemical equations:
`"H"_2"S"` + `"CI"_2` `→`
Fill in the blank
A catalyst either ................or ............... the rate of a chemical change but itself remains ............... at the end of the reaction.
What are oxides ?
Choose the correct option from the bracket and explain the statement giving reason.
(Oxidation, displacement, electrolysis, reduction, zinc, copper, double displacement, decomposition)
To prevent rusting, a layer of ______ metal is applied on iron sheets.
Complete the statement by filling the gaps using appropriate term from the terms given in the bracket.
(slow, coloured, arrow, fast, smell, milky, physical, product, chemical, reactant, covalent, ionic, octet, duplet, exchange, sharing, equality sign)
Oxygen is a ______ in respiration.
Show with the help of diagram of electronic configuration how the following compound is formed from the constituent atoms.
Potassium fluoride
Define Photochemical reaction
Give an example
Give an example of the following chemical change.
Two gases combine to form white solid
Give reason for the following:
Blue solution of copper sulphate changes to green when a piece of iron is added to this solution.
Explain,giving one example of the following chemical changes:
Reversible reaction
Name Affects the acidified K2Cr2O7 paper and also turns lime water dirty milky.
Give a chemical test to distinguish between the following gases.
CO2 and SO2
Write your observation and a balanced equation in the case of the following substances being heated.
Zinc carbonate.
Give examples of exothermic reactions i.e. heat evolved in each of the following:
(a) reaction between a solid and a liquid
(b) reaction between two gases
Give two examples of exothermic reactions seen in everyday life.
Give reason for the following:
The catalytic oxidation of sulphur dioxide to sulphur trioxide is represented by a double arrow {⇌}
between the reactants and products, formed in the chemical reaction.
Give balanced equation for the following conversion affected by heat alone on the substance:
Copper carbonate to copper oxide
Give balanced equation for the following conversion affected by heat alone on the substance:
Zinc nitrate to nitrogen dioxide
What kind of a change is associated with decaying of a plants?
________ is a chemical substance which alters the speed of a chemical reaction.
Silver articles turning black: ______:: Boiling of H2O: physical change ______.
Give an example of a chemical reaction for each of the following situations:
A change in colour is observed.
______ occurs in the absence of air and in the presence of micro-organisms such as yeast.
Write the equation for the process of formation of rust.
Give an example where heat, light, and sound are produced during a chemical change.
Write a note on the following:
Curdling of milk
Photosynthesis is a chemical charge. Justify your answer.
______ is the chemical name of slaked lime.
