Q.1

Different microorganisms taking part in the nitrogen cycle are:
(i) Rhizobium in roots
(ii) Ammonifying bacteria
(iii) Nitrifying bacteria
(iv) Denitrifying bacteria
Which of them strictly work under anaerobic conditions?

Q.2

Identify the element as per following statement:

An element reacts with oxygen to give a compound with a high melting point. This compound is also soluble in water. 

Q.3

Which one of the following is the correct sequence of the reactivity order of the elements?

Q.4

Shalini was walking on ice, her mother advised her to take smaller steps to avoid slipping. Which of the following could be the reason for the smaller steps?

Q.5

Which of the following pairs cannot undergo displacement reaction?

Q.6

Which of the following can lead to menstruation in a 21-year-old woman during ovulation?
A. Sperms not available for fertilisation
B. Oviducts blocked
C. Sperms available for fertilisation
D. Oviducts not blocked

Q.7

Consider the following statements about the physical and chemical properties of metals and choose the correct option:

1. All metals are ductile.
2. Generally metals are ductile.
3. Metals which are more reactive than hydrogen react with acids to release hydrogen gas.
4. All metals react with acids to release hydrogen gas.

Q.8

Read the following statements and choose the correct option:

Statement 1: The antibiotic penicillin inhibits the growth of bacteria by blocking the process which helps to build its cell membrane.

Statement 2: The cell membrane is selectively permeable because it allows the movement of certain molecules in and out of the cell while the movement of other molecules is prevented.

Q.9

Arrange the different types of coal in the decreasing order of the quality of coal:

(1) Lignite
(2) Peat
(3) Anthracite
(4) Bituminous

Q.10

Which of the following problem is not related to our environment?