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प्रश्न
Give reasons
Graphite is used in the leads of pencils
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उत्तर
Graphite turns paper black that is why it is used in the leads of pencils.
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संबंधित प्रश्न
Mark ‘T’ if the statement is true and ‘F’ if it is false.
Sodium is a very reactive metal. ( )
A metal having low melting point is ______ but a non-metal having very high melting point is ______.
What is meant by 22 carat gold?
What is an alloy?
Fill in the blank
_______ is a soft metal.
Write ‘true’ or ‘false’ for the following statement :
Silver is used to make electric cables.
State two important uses of following metals:
Uses of iron
State two important uses of the following metal.
Uses of magnesium
State the position of the following in the periodic table:
Aluminium
Why is hydrogen placed with alkali metals?
Take an element from an alkali metal and one from an alkaline earth metal and write an equation for their action with:
Water.
Write scientific reason.
Sodium is always kept in kerosene.
When a copper coin is dipped in silver nitrate solution, a glitter appears on the coin after some time. Why does this happen? Write the chemical equation.
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 crystalline solid which decrepitates on heating leaving a residue which fuses with the glass and evolves two gases one of which is coloured and acidic.
Aluminium: _______: gold : : electric insulator
Give reasons for the following.
- Aluminum foils are used to wrap food items.
- Immersion rods for heating liquids are made up of metallic substances.
- Sodium and potassium are stored in kerosene.
- Mercury is used in thermometers.
Which of the following property is generally not shown by metals?
Why are bells made of metals?
X [2, 8, 7] and Y [2, 8, 2] are two elements. Using this information, complete the following:
______ is the metallic element.
