Question
Name two metals which react violently with cold water. Write any three observations you would make when such a metal is dropped into water. How would you identify the gas evolved, if any, during the reaction?

Answer

Sodium and potassium metals react violently with cold water Observations:
  1. Metal starts moving over the surface of water making a hissing sound.
  2. Metal starts reacting with water causing little explosions.
  3. Soon the metal catches fire and starts burning.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

An object is placed at a distance of 10 cm from a convex mirror of focal length 15 cm. Find the position and nature of the image.
Depletion of ozone in the ozone layer is a cause for our worry. Why?
What is hypertension? Why is it caused? What harm can it do?
$i$. A wire of resistance $2$ has been connected to a source of $50 V$ as its two ends. What is the current flowing through the wire?
$ii.$  An electric refrigerator rated $400 W$ operates $8$ hour/day. What is the cost of the energy to operate it for $30$
days at $₹ 3.00 \ \text{per kWh}$ ?
What is a lens? Distinguish between a convex lens and a concave lens. Which of the two is a converging lens : convex lens or concave lens?
An electric iron is connected to the mains power supply of 220V. When the electric iron is adjusted at ‘minimum heating’ it consumes a power of 360W but at ‘maximum heating’ it takes a power of 840W. Calculate the current and resistance in each case.
Why is the leakage of LPG detected easily although it is odourless? State the steps to be taken in case its leakage is detected in the kitchen.
Explain how, a reduction reaction of aluminium can be used for welding cracked machine parts of iron. Write a chemical equation for the reaction involved.
When a green iron salt is heated strongly, its colour finally changes to brown and odour of burning sulphur is given out:
  1. Name the iron salt.
  2. Name the type of reaction that takes place during the heating of iron salt.
  3. Write a chemical equation for the reaction involved.
The near-point of a person suffering from hypermetropia is at 50cm from his eye. What is the nature and power of the lens needed to correct this defect ? (Assume that the near-point of the normal eye is 25cm).