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Question
______ gas causes tears in our eyes while cutting onions.
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Solution
Propanethial s-oxide gas causes tears in our eyes while cutting onions.
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RELATED QUESTIONS
Changes in which new substances are formed are called ______ changes.
Define catalyst.
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
TRUE \ FALSE
Weak electrolytes dissociate partially in their aqueous or fused state.
TRUE \ FALSE
Positively charged electrode is called the anode. True or false ?
Write true or false :
No new substance is formed during a chemical reaction.
What is the reaction called when oxidation and reduction take place simultaneously? Explain with one example.
Give an example of a reaction where the following are involved:
Solution
Give an example of the following chemical change.
A reaction where colour change is noticed
Multiple choice:
A reaction of a type: AB + CD → AD + CD, involves
Give balanced equation for the following conversion affected by heat alone on the substance:
Hydrated copper sulphate to sulphur dioxide
Match the chemical reactions in List I with the appropriate answer in List II.
| List I | List II | ||
| 1. | \[\ce{XY⇌[heat]X + Y}\] | A: | Displacement reaction |
| 2. | \[\ce{XY->X + Y}\] | B: | Double decomposition |
| 3. | \[\ce{X+Y- + A+B^-->X+B- + A+Y-}\] | C: | Endothermic reaction |
| 4. | \[\ce{X + YZ->XZ + Y}\] | D: | Thermal dissociation |
| 5. | \[\ce{X + Y->[heat]XY -\Delta}\] | E: | Decomposition reaction |
Complete the statement by filling in the blank with the correct word:
The reddish-brown precipitate obtained during a double decomposition precipitation reaction between an iron salt and alkali is __________.
Select the correct answer from the options given below:
State the gaseous product formed, when
An ammonium salt reacts with an alkali.
Explain the following statement: Digestion is a chemical change.
Write some materials prepared by chemical changes.
Arrange the following statements in correct sequence:
- One side is water-loving and other water-hating molecules.
- When you agitate the cloth, the dirt is surrounded by many molecules and taken away from the cloth.
- The dirt surrounded by the detergent molecules floats in the water making it dirty.
- Finally, the cloth is clean.
- The detergent molecules have two sides.
- Water hating goes and joins with dirt and oil in the cloth while the water-loving joins with the water molecules.
Classify each of the following, as a physical or a chemical change. Give reasons.
(a) Drying of a shirt in the sun.
(b) Rising of hot air over a radiator.
(c) Burning of kerosene in a lantern.
(d) Change the colour of black tea by adding lemon juice to it.
(e) Churning of milk cream to get butter.
A chemical change may involve –
Is the conversion of milk into ice cream a chemical change?
