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Question 42
When a metal X is treated with cold water, it gives a base Y with molecular formula XOH (Molecular mass = 40) and liberates a gas Z, which easily catches fire. Identify X, Y and Z and also write the reaction involved.

Question 7
Organisms which synthesize carbohydrates from inorganic compounds using radiant energy are called

(a) decomposers
(b) producers
(c) herbivores
(d) carnivores

From the following balances of M/s Nilu Sarees as on 31st March, 2016.
Prepare trading and profit and loss account and balance sheet as on date.

$\begin{array}{cccc}\text{Particulars}& \text{Amt (Rs.)}& \text{Particulars}& \text{Amt (Rs.)}\\ \text{Opening Stock}& 10,000& \text{Sales}& 2,28,000\\ \text{Purchases}& 78,000& \text{Capital}& 70,000\\ \text{Carriage Inwards}& 2,500& \text{Interest}& 7,000\\ \text{Salaries}& 30,000& \text{Commission}& 8,000\\ \text{Commission}& 10,000& \text{Creditors}& 28,000\\ \text{Wages}& 11,000& \text{Bills Payable}& 23,700\\ \text{Rent and Taxes}& 2,800& & \\ \text{Repair}& 5,000& & \\ \text{Telephone Expenses}& 1,400& & \\ \text{Legal Charges}& 1,500& & \\ \text{Sundry Expenses}& 2,500& & \\ \text{Cash in Hand}& 12,000& & \\ \text{Debtors}& 30,000& & \\ \text{Machinery}& 60,000& & \\ \text{Investments}& 90,000& & \\ \text{Drawings}& 18,000& & \end{array}$

Closing stock as on 31st March, 2016 Rs. 22,000.

Which of the following statements regarding the periodic trends of chemical reactivity of the alkali metals and the halogens is correct?

How do electronic configurations of elements change in second period of periodic table with increase in atomic numbers ?

What are the observations when lead nitrate is heated?

Fill in the following blanks with suitable words :

(a) Chemical equations are balanced to satisfy the law of ..........

(b) A solution made in water in known as an .............. solution and indicated by the symbol .......

1. 7

The ions which impart acidic properties to an aqueous solution of hydrogen chloride are:

What is the value of the enthalpy of neutralization for all strong acids and bases?

Metals like iron, copper, aluminium and zinc are given to a student. The correct decreasing order of reactivity of these metals written by the student is:

At STP air contains 22.4% by volume of oxygen. The number of moles of oxygen present in 1 litre of air are

(a) Match the formulae in group A with appropriate names from group B :
Group A: $C{H}_{3}COOH,C{H}_{3}CHO,C{H}_{3}OH$
Group B: Ethanol, Methanol, Ethanal, Ethanoic acid
(b) Draw the structure of butanoic acid.
(c) What is the IUPAC name of acetic acid?

How many chain isomers does a compound having molecular formula ${\text{C}}_5{\text{H}}_{10}$ has?

In an aqueous solution if $F^{-}$ ions are present then

Explain why the number of atoms in one mole of hydrogen gas is double the number of atoms in one mole of helium gas?

(a) What is the common name of the compound $CaOC{l}_2$ ?

(b) Name the raw material used for the preparation of plaster of Paris.

(c) Which property of plaster of plaster of Paris is utilised in making casts for broken limbs in hospitals ?

(d) Explain why chlorine is used for sterilising drinking water supply.

Name the metal which is a constituent of:

(a) blood pigment, (b) plant pigment.

1. 16

For a reversible system, when the pressure of the reacting system in equilibrium is increased then

Generally, for which of the following ores, froth floatation method is used for concentration?

A reaction proceeds five times faster at $57{}^{\circ }C$ as it does at $27{}^{\circ }C$. The energy of activation is:
(take $ln3=1.1,ln5=1.6$)

Analyse the given compound below

How many carbon atoms are there in the longest chain?

Which of the following transition elements will have a half-filled d-orbital?

The size of species $I$, $I^{\oplus }$ and $I^{\ominus }$ decreases in the order

In $C+H_{2}O⟶CO+H_2,H_{2}O$ acts as

Select the correct answers :

(a) Colour of an aqueous solution of copper sulphate is

(i) Green (ii) Brown (iii) Blue (iv) Yellow

(b) Colour of the precipitate formed on adding $NaOH$ solution to iron (II) sulphate solution is

(i) White (ii) Brown (iii) Green (iv) Pale blue

(c) A metal which produces hydrogen on reacting with alkali as well as with acid.

(i) Iron (ii) Magnesium (iii) Zinc (iv) Copper

$C{H}_{4}and{C}_2{H}_6$ form a homologous series, they differ by:

Methane is a green house gas. Comment.

Which of the following is cyanide process?

Choose the molecule which exhibits polar character.

Write short note on :
(i) Catenation (ii) Glacial acetic acid (iii) Saponification

State the position of the following in the Periodic Table:

(a) Alkali metals, (b) Alkaline earth metals,

(c) Iron and zinc, (d) Aluminium.

Which of the following van der waals radii is the largest

Complete the following reaction:
$C_2{H}_6+\mathrm{conc}.{\mathrm{HNO}}_3\stackrel{400°C}{\to }$ $+H_{2}O$

the difference of molecules of water in gypsum and pop is

The common name of ethanoic acid is:

Complete and balance the given chemical reaction.
${\text{CH}}_3{\text{CH}}_2{\text{CH}}_2{\text{CH}}_3\text{(g)}+{\text{O}}_2\text{(g)}\to$

(a) What happens during a bee sting? What is its remedy?

(b) What happens during a wasp sting? What is its remedy?

Li⁺ and Cs⁺ ions form hydrated ions as [ Li(H₂O)_x]⁺ and [Cs(H₂O)_y]⁺ . Then 'x' and 'y' are related as

Populations of insects and green plants in a particular region is always balanced.This balance and equilibrium is achieved by various processes in:

One of the following helps in the recycling of materials in an ecosystem. This one is:

(a) autotrophs (b) saprotrophs (c) omnivores (d) carnivores