IMPORTANT QUESTIONS

1. Q391 If an iron nail is immersed in the aqueous solution of copper sulphate, what are the changes happening to the nail and to the solution?

   Easy View solution
2. Q392 Which is correct

   • (a)Galena: Mg₂CO₃
   • (b)Cassiterite: CaCO₃ MgCO₃
   • (c)Dolomite: SnO₂
   • (d)Magnesite : MgCO₃

   Easy View solution
3. Q393 An element reacts with oxygen to give a compound with a high melting point. The compound is soluble in water. The element is likely to be

   • (a)Calcium
   • (b)Carbon
   • (c)Iron
   • (d)Silicon

   Easy View solution
4. Q394 Write one structural difference between the composition of artery and veins

   Easy View solution
5. Q395 The atomic number of an element is 16. Predict the nature of oxide formed by it

   Easy View solution
6. Q396 Give a way to prevent sexually transmitted diseases.

   Easy View solution
7. Q397 Atom of an element contains five electrons in its valence shell. This element is major component of air. It exists as a diatomic molecule. Show the bond formed between two atoms of this element.

   Easy View solution
8. Q398 In an experiment to trace the path of a ray of light through a glass prism for different values of angle of incidence a student would find that the emergent ray:

   • (A)is parallel to the incident ray
   • (B)perpendicular to the incident ray
   • (C)is parallel to the refracted ray
   • (D)bends at an angle to the direction of incident ray

   Easy View solution
9. Q399 What happens when ZnCO₃ is heated in the absence of air? Give the relevant equation. Chemical reaction of Zinc metal and NaOH is Zn +2NaOH →Na₂ZnO₂ + H₂

   Medium View solution
10. Q400 A security mirror used in a big showroom has radius of curvature 5 m. If a customer is standing at a distance of 20 m from the cash counter, find the position, nature and size of the image formed in the security mirror

    Medium View solution