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Atoms consists of electrons, protons and neutrons as the fundamental particles. The electrical charge of an atom will be ___.

1. 2

The two of the most important properties of carbon would be: catenation and __.

The freezing point depression constant $\left(K_f\right)$ of benzene is $5.12{\text{K kgmol}}^{-1}$. The depression of freezing point for the solution of molality $0.078\text{m}$ containing a non-electrolyte solute in benzene is (rounded off upto two decimal places):

Explain how, the smell of food being cooked in the kitchen reaches us even from a considerable distance.

The teacher took 2 beakers and said, "I am adding Cl-35 in the first beaker and adding Cl-37 in the second beaker. What do you think will be the valency of the two types of the chlorine atoms?"

An element ‘X’ has mass number = 27. If the number of electrons is given as 13, the number of neutrons will be _____.

Is it possible to liquify atmospheric gases? If yes, suggest a method.

Rutherford's experiment, which established the nuclear model of the atom, used a bottom of:

State whether the following statements are true or false:
(a) Thomson proposed that the nucleus of an atom contains protons and neutrons.
(b) The cathode rays obtained from all the gases consist of negetively charged particles called electrons.
(c) The anode rays obtained from all the gases consist of positively charged particles called protons.

Two elements A and B have valencies of 5 and 3, and 3 and 2, respectively. The elements A and B are most likely to be respectively:

Question 6

A dilute ferrous sulphate solution was gradually added to the beaker containing acidified permanganate solution. The light purple colour of the solution fades and finally disappears.

Which of the following is the correct explanation for the observation?

(a) ${\text{KMnO}}_4$ is an oxidizing agent, it oxidises ${\text{FeSO}}_4$.
(b) ${\text{FeSO}}_4$ acts as an oxidizing agent and oxidises ${\text{KMnO}}_4$.
(c) The colour disappears due to dilution; no reaction is involved.
(d) ${\text{KMnO}}_4$ is an unstable compound and decomposes in presence of ${\text{FeSO}}_4$ to a colourless compound.

In Rutherford's alpha particle scattering experiment, what was the percentage (approx.) of the incident $\alpha -$particles scatter by more than $1^{\circ }?$

What is relative molecular mass and relative atomic mass? [2 MARKS]

(c) All ammonium salts are decomposed on heating. What other property do ammonium salts have in common?

When steam is passed over red-hot coke it forms:

We Can easily move our hand in air but to do the same through a solid block of wood we neednan karate expert. Why?

Why does our plan feel cold when we put some Acetone or perfume on it

Which of the following numbers represents the water of crystallization of blue vitriol?

$HN{O}_2+2H_{2}S{O}_3+H_{2}O\to N{H}_{2}OH+2DThen‘D^{\prime }is$

The day of reopening of the school after summer break was coming closer for Rahul, a student of class 9. He went to the market to buy some stationary for himself. His mother told him to get a packet of salt also with him. When Rahul was coming back from the market the bag got split and the things fell on the ground. He started collecting the things but while doing so the things got mixed up. He somehow collected everything and reached home. The mother saw that the salt was mixed up with sand and stapler pins. Now answer the following questions in the chemistry notebook.
. Write the steps to separate sand, salt and stapler pins suggesting Rahul.

When washing soda remove in open air the only nine molecules of water get evoporate rather ten.

Which ions formed from hypochlorous acid form the basis for the bleaching action of chlorine?

Which of these statements is incorrect about hydrogen gas?

What is a solution? What are the properties of a solution?

Which of the following is known as carborundum?

Two radioactive samples $\text{A and B}$ have half lives $T_1$ and $T_2$ $(T_1>T_2)$ respectively. At $t=0$, the activity of $\text{B}$ was twice the activity of $\text{A}.$ Their activity will become equal after a time-

The electronic configuration of silver atom in ground state is