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प्रश्न
Write true or false.
A chemical equation gives only qualitative information of a chemical reaction.
विकल्प
True
False
उत्तर
False
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संबंधित प्रश्न
How would you show that setting of curd is a chemical change?
Give one example that illustrates the following characteristics of a chemical reaction:
Change in state
Complete and balance the following chemical equations:
Zn + `"H"_2"SO"_4` `→`
(dil)
Fill in the blank
A change in which the substance can be brought back to its original state is called a _______ change.
Fill in the blank:
The substances formed as a result of a chemical reaction are called _______
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)
The white particles of baking soda disappear when put in lemon juice. This means that it is a ______ change.
Explain by writing a word equation.
Limestone powder disappears on adding to dilute hydrochloric acids.
Show with the help of diagram of electronic configuration how the following compound is formed from the constituent atoms.
Water
Define the following terms
Precipitate
Give an example of the following chemical change.
Two solids combine to form a liquid
Give reason for the following:
Molybdenum is used in the manufacture of ammonia.
What do you observe? When
Water is added to the quick lime.
Complete the following table and write your observations.
|
Hydrogen sulphide |
Ammonia |
Sulphur dioxide |
Hydrogen chloride |
|
|
Shake the gas with red litmus solution |
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Shake the gas with blue litmus solution |
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Apply a burning splint to a gas |
What do you observe when Cobalt chloride paper is introduced in water vapour.
What do you observe when dilute sulphuric acid is added to the following:
Sodium Sulphide
Select the correct answer for the following options:
The basic gas obtained when two gases react in presence of a catalyst and the reaction is exothermic.
Select the correct answer for the following options:
The pale blue precipitated obtained when copper [II] sulphate reacts with sodium hydroxide.
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.
Name the following:
The products obtained during ‘photosynthesis’ – which is a chemical change.
On heating which of the following substances i.e. copper carbonate, zinc carbonate, washing soda, copper sulphate, zinc nitrate, copper nitrate, lead nitrate, ammonium chloride and ammonium dichromate – relate to the reaction given below.
A white solid which evolves two colourless gases which on cooling combine and condense on the cooler parts of the test tube.
Explain the Silver nitrate solution is kept in coloured reagent bottles in the laboratory.
State the following reaction represent oxidation or reduction.
\[\ce{H->H+}\]
A chemical reaction is often accompanied by external indications or characteristics.
Explain with the help of balanced equations, how precipitation reactions are used for identifying the positive radicals in three different salts, each having a different cation [positive ion].
What happens when cane sugar is strongly heated? Mention any two changes in it.
Higher order Thinking question
A very hot glass on putting in cold water cracks. What does this change indicate?
On heating calcium carbonate gets converted into calcium oxide and carbon dioxide.
(a) Is this a physical or a chemical change?
(b) Can you prepare one acidic and one basic solution by using the products formed in the above process? If so, write the chemical equation involved.
We are advised to not to play with fireworks. Give reason.
Assertion (A): Cutting paper into very small pieces is an irreversible change.
Reason (R): Physical changes are always reversible.
