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Complete the following reaction:



${\text{Na}}_2{\text{CO}}_3\text{(s)}+{\text{H}}_2{\text{SO}}_4\text{(aq)}\to ?$

Getting people out of a building in case of fire is called ____.

If you mix dilute HCl and zinc granules in a test tube, ____ gas will be released.

Which of the following noble gases is preferably used for providing inert atmospheres during welding metals?

A dilute aqueous solution of $N{a}_{2}S{O}_4$ is electrolysed using platinum electrodes. The product at anode and cathode, respectively are:

Which of the following is the most abundant element in the universe?

Pick the odd one from the following elements.

Question 7:

Give examples of desirable and undesirable changes.

Acetone and water are ____ liquids and can be separated by ___ .

The maximum number of electrons in an orbit can be calculated by ___

Medicines that have the instructions 'shake the bottle well before use', are most likely

"जब संगीत की स्वर लहरी गूँजती है तो पशु-पक्षी तक मुग्ध हो जाते हैं, शायर साहब! आप क्या समझते हैं संगीत को?"

इस संवाद को पढ़ो और बाताओ कि–

(क) कहानी में इसके बदले किसने, क्यों और क्या बोला? तुम उसको लिखकर बताओ।

(ख) कहानी में शायर के बदले गाजर कहने से क्या हुआ? तुम भी अगर किसी शब्द के बदले किसी अन्य शब्द का प्रयोग कर दो तो क्या होगा?

Substances that are formed as a result of a chemical reaction are called ________ and are written on the ________ side of the equation.

Let $X$ and $Y$ be two elements. The formula of a compound made up of $X$ and $Y$ is $X_2{Y}_3$. For a molecule of the compound, the ratio between the Y and X atoms is:

A ____________ is dissolved in another substance called __________ to form a solution.

Identify the correct reactant and product(s) among the following options when the reactant reacts with hydrochloric acid.

How does anomolous expansion of water help the aquatic organisms in cold climates ?

Which of the following arrangements represent possible presentations of Bohr’s model of an atom correctly?

(a) Explain the structure of candle flame. Also, draw its diagram.

(b) What is calorific value?

(c) What are the characteristics of a good fuel?

A reaction in which a more reactive metal replaces a less reactive metal from its salt solution is called ___ reaction.

Question 4

Which postulate of Dalton’s atomic theory can explain the law of definite proportions?

One atomic mass unit (amu) is closest to:

Observe the table and identify metals and nonmetals. Select the correct option.
$\begin{array}{ccc}\text{Sl.No}& \text{Set-1}& \text{Set-2}\\ \text{1.}& \text{Sodium(Na)}& \text{Oxygen(O)}\\ \text{2.}& \text{Magnesium(Mg)}& \text{Chlorine(Cl)}\\ \text{3.}& \text{Iron(Fe)}& \text{Helium(He)}\\ \text{4.}& \text{Gold(Au)}& \text{Sulphur(S)}\\ \text{5.}& \text{Calcium(Ca)}& \text{Carbon(C)}\end{array}$

A pouch of a chemical powder is placed in some bottles of medicines. What is this chemical? Why is it placed there?

A car weighing 700 kgf changes its speed from 36 km/h to 72 km/h in 2 minutes. What is the work done by the engine? Consider $g=10m/s^2$



[1 mark]

Which among the following is electropositive element?

Which of the following does not involve a combustion reaction ?

(a) production of heat and light from kerosene in a lantern

(b) production of heat and light from hydrogen in a rocket

(c) production of heat and light from hydrogen in the sun

(d) production of heat and light from wood in a bonfire

Question 7:

Write down the uses of base.