Advertisements
Advertisements
प्रश्न
Write true or false .
A black residue is formed when sugar is heated .
विकल्प
True
False
Advertisements
उत्तर
True
APPEARS IN
संबंधित प्रश्न
The gas we use in the kitchen is called liquefied petroleum gas (LPG). In the cylinder, it exists as a liquid. When it comes out from the cylinder it becomes a gas (Change − A), then it burns (Change − B). The following statements pertain to these changes. Choose the correct one.
MULTIPLE CHOICE QUESTIONS
Tick the most appropriate answer.
Compounds, which in their molten state allow an electric current to pass through them are called
- electrolytes
- non-electrolytes
- non-conductors
- none of these
FILL IN THE BLANK
In a ............ change, new substances are formed.
Fill in the blank.
Melting of ice is a _______ change.
Balance the following equation :
Fe + H2O → Fe3O4 + H2
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)
Chlorine (Cl2) molecule is formed by ______ of electrons between two chlorine atoms.
Choose the correct option from the bracket and explain the statement giving reason.
(Oxidation, displacement, electrolysis, reduction, zinc, copper, double displacement, decomposition)
The conversion of ferrous sulphate to ferric sulphate is ______ reaction.
Explain the term reactant and product giving examples.
State the main characteristics of chemical reactions. Give at least one example in each case.
Name the gases which turn moist red litmus blue.
Give a chemical test to distinguish between the following gases.
NH3 and HCl
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 coloured substance which leaves a black residue and evolves two gases one of which is acidic and coloured and the other neutral and colourless.
Explain the Silver nitrate solution is kept in coloured reagent bottles in the laboratory.
Give a suitable example with an equation to show the representation of a chemical reaction.
______ is not a chemical change.
Explain the following statement: Digestion is a chemical change.
Match the following:
| Column I | Column II | ||
| 1. | Burning of coal | a. | Rusting |
| 2. | Painting of a surface | b. | Evaporation |
| 3. | Dipping iron in the water | c. | Chemical change |
| 4. | Salt from seawater | d. | Prevention of rusting |
______ is the chemical name of slaked lime.
______ is the chemical name of limestone.
Write the effects of chemical reactions.
