Metals and Non-Metals — Science STD 10 — Question

Food cans are coated with tin and not with zinc because.

A student while observing an embryo of a pea seed in the laboratory listed various parts of the embryo as given below : Testa, Tegmen, Radicle, Plumule, Micropyle, Cotyledon. On examining the list the teacher remarked that only three parts are correct. Select three correct parts from the above list :

Lack of oxygen in muscles often leads to cramps among cricketers. This results due to :

Suppose you have focused on a screen the image of candle flame placed at the farthest end of the laboratory table using a convex lens. If your teacher suggests you to focus the parallel rays of the sun, reaching your laboratory table, on the same screen, what you are expected to do is to move the :

On moving from left to right in a period of the periodic table, the atomic number of elements increases. What happens to the size of atoms of elements on moving from left to right in a period?

A decrease in the grass population will most immediately decrease the available energy for the :

Vinegar is a solution of:

Assertion (A): Colour of copper sulphate solution changes when an iron nail is kept immersed in it.
Reason (R): The colour of copper sulphate solution changes when iron nail is kept immersed in it due to the decomposition reaction taking place between iron and copper leading to formation of iron sulphate.

While preparing soap a small quantity of common salt is generally added to the reaction mixture of vegetable oil and sodium hydroxide. Which one of the following may be the purpose of adding common salt?

Which of the following elements will form an acidic oxide?