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Question 9:

The label on the bottle of chemicals is spoiled. How will you find whether the chemical is acidic or not?

Observe the picture given in Figure carefully and answer the following questions.​



(a) What is covering the nose and mouth of the policeman?​

(b) Why is he putting a cover on his nose?

(c) Can you comment on air quality of the place shown in the figure?

Match the
items in Column I with those in Column II:

Through which of the following process does the fresh water becomes available on land?

Which of the following statement is incorrect in case of sodium chloride?

Elements of the same group have

Water purification refers to________.

Identify the monoatomic and polyatomic ions from the following equation-
$Pb(N{O}_3{)}_2$ + $K_{2}S{O}_4$ $\to$ $2KN{O}_3$ + $PbS{O}_4$

As shown in the given figure, the clothes get dried because:

Which type of soil is best known for growing plants and why? [3 MARKS]

Define the following with suitable examples.

(i) Natural and Manmade change

(ii) Periodic and Non periodic change

(iii) Temporary and Permanent change

Activated sludge is produced in which tank?

Which of the following is a physical disinfectant?

Which of the following observation are the signs of depletion of groundwater?

Specific conductance of a decimolar solution of $KCl$ at $25{}^{\circ }\text{C}$ is $1.12{\text{S m}}^{-1}$. The resistance of a cell containing the solution at $25{}^{\circ }\text{C}$ was found to be $50\Omega$. The cell constant is:

Calculate the wavelength of de-Broglie waves associated with a neutron at room temperature of ${27}^{\circ }\text{C}$. Given the mass of the neutron, $m=1.67\times {10}^{-27}\text{kg}$, Boltzmann constant, $k=1.38\times {10}^{-23}{\text{J K}}^{-1}$ and $h=6.6\times {10}^{-34}\text{Js}$.

Which of the following will be most stable diazonium salt $R{N}_2^{+}{X}^{-}$ ?

Atomic number of calcium is 20. Calculate the number of electrons in calcium.

Which acid does grains contain??

Identify the reactant in the given reaction:

$+H_{2}S{O}_4\to N{a}_{2}S{O}_4+C{O}_2+H_{2}O$

The rate constant for a first order reaction is $4.606\times {10}^{-3}{s}^{-1}$. The time required to reduce $2.0g$ of the reactant to $0.2g$ is:

For the given reaction, which of the following expressions is correct?



$Br{O}_3^{-}\left(aq\right)+5B{r}^{-}\left(aq\right)+6H^{+}\to 3B{r}_2\left(l\right)+3H_{2}O\left(l\right)$

1. A ____________________ represents one atom of an element.

Match the following:

$\begin{array}{cccc}\left(i\right)& \text{Water}& \left(A\right)& \text{Compound}\\ \left(ii\right)& \text{Hydrogen}& \left(B\right)& \text{Element}\\ \left(iii\right)& \text{Salt}& & \\ \left(iv\right)& \text{Gold}& & \\ \left(v\right)& \text{Carbon dioxide}& & \\ \left(vi\right)& \text{Iron}& & \end{array}$
The correct pairs are:-

If there's an Oxygen in the acid then the probability of having -hydro is _________

Is the distilled water acidic, basic or neutral? How would you verify it? [3 MARKS]

In the distillation apparatus is there any reason for the two water outlets??

What is a litmus paper? What would happen when a red litmus paper is treated with a solution containing NaOH? [2 MARKS]