Download App

Metals and Non-Metals — Science STD 10 — Question

CBSE BoardEnglish MediumSTD 10ScienceMetals and Non-Metals3 Marks
Question
When a metal X is treated with cold water, it gives a basic salt Y with molecular formula XOH (Molecular mass = 40) and liberates a gas Z which easily catches fire. Identify X, Y and Z and also write the reaction involved.
✓

Answer

solution The atomic mass of metal $X=56$ - Mass of OH group $=56-17=39 u$. This shows that the metal ' $X$ ' is potassium $( K )$ and the basic salt ' $Y^{\prime}$ ' is potassium hydroxide $( KOH )$. It is formed by reacting potassium with cold water. Hydrogen gas 'Z' evolved in the reaction catches fire.
$2 K(s)+2 H_2 O(aq) \rightarrow 2 KOH(aq)+H_2(g)$

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

Explore more

More "[3 Mark Questions]" from Metals and Non-Metals→Metals and Non-Metals — all question types→Science STD 10 question papers→CBSE Board STD 10 question papers→CBSE Board question paper generator→

Similar questions

Give the exact location and function of the cerebellum.
→
What is a dam? Why do we seek to build large dams? While building large dams, which three main problems should particularly be addressed to maintain peace among local people? Mention them.
→
How can ethanol and ethanoic acid be differentiated on the basis of their physical and chemical properties?
→
An object is kept at a distance of 5cm in front of a convex mirror of focal length 10cm. Calculate the position and magnification of the image and state its nature.
→
Ferrous sulphate decomposes with the evolution of a gas having a characteristic odour of burning sulphur. Write the chemical reaction involved and identify the type of reaction.
→
What is an ammeter? How is it connected in a circuit? Draw a diagram to illustrate your answer.
→
What is vegetative propagation? State two advantages and two disadvantages of this method.
→
A person got his eyes tested by an optician. The prescription for the spectacle lenses to be made reads:
Left eye: +2.50D, Right eye: +2.00D
  1. State whether these lenses are thicker in the middle or at the edges.
  2. Which lens bends the light rays more strongly?
  3. State whether these spectacle lenses will converge light rays or diverge light rays.
→
Five solutions A, B, C, D and E when tested with universal indicator showed pH as 4, 1, 11, 7 and 9, respectively. Which solution is
  1. Neutral?
  2. Strongly alkaline?
  3. Strongly acidic?
  4. Weakly acidic?
  5. Weakly alkaline?
Arrange the pH in increasing order of hydrogen-ion concentration.
→
  1. Explain the terms:
  1. Implantation.
  2. Placenta.
  1. What is the average duration of human pregnancy?
→