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Which of the following are mineral acids?

Considering the elements B, AI, Mg, and K, the correct order of their metallic character is:

1. 14

The gas mixture used by Miller in his experiment comprised:

Which acid is produced in our stomach? What happens if there is an excess of acid in the stomach? How can its effect be cured?

A colourless and odourless gas is liberated when hydrochloric acid is added to a solution of washing soda. The name of the gas is:

Ionic radii vary in
(a) inverse proportion to the effective nuclear charge
(b) Inverse proportion to the square of effective nuclear charge
(c) direct proportion to the screening effect
(d) direct proportion to the square of screening effect

What is obtained when ${\text{NaHCO}}_3$ is heated?

What is chemical change?

The geometry and the type of hybrid orbitals present about the central atom in $B{F}_3$ is

The number of valence electrons in a sulphur atom are ___ and in $S_8$ each sulphur is bonded to ___ other sulphur atom(s).

The molecular formula for elemental sulphur is $S_8$. In a sample of 5.12 g of slphur:
(a) How many moles of sulphur are present?
(b) How many molecules and atoms are present?

Which metal foil is used for packing some of the medicine tablets?

An ecosystem includes :

(a) all living organisms

(b) non-living objects

(c) both living organisms and non-living objects

(d) all living organisms and input of sun's energy

(a) Name two metal s which occur in nature in free state as well as in combined state
(b) Name one ore of manganese. Which compound of manganese is present in this ore? Also write its chemical formula.
(c) A zinc ore on heating in air forms sulphur dioxide. Describe briefly any two stages involved in the conversion of this concentrated ore into zinc metal.

Which of the following burns by producing a yellow, luminous flame ?
(a) natural gas (b) coke (c) wax (d) charcoal

Write method to prevent rancidity? What is rancidity?

Which of the following statement(s) is/are correct?

I. Selective discharge of ions is independent of the relative position of ions in the activity series.

II. Selective discharge of ions is dependent on nature of electrodes.

7 uses of Hydrogen ?

Calculate the no of molecules present in one kg of calcium chloride

(a) Give IUPAC names and formulae of an organic compound containing single bonds and the other containing a triple bond.
(b) Which of the following is the molecular formula of benzene?
$C_6{H}_6,C_6{H}_{10},C_6{H}_{12},C_6{H}_{14}$
(c) Which of the two has a branched chain: isobutane or normal butane?

When potassium nitrate is heated, it decomposes into potassium nitrite and oxygen. Write a balanced equation for this reaction and add the state symbols of the reactants and products.

What type of polarity develops on the copper and zinc electrodes in a voltaic cell? What is the value of the potential difference developed between them?

Why can't carbon form bond of 4 electrons with another carbon ?

Does Hydrogen have a proper place assigned to it in the Modern Periodic Table? Explain.

Graphite is a soft lubricant extremely difficult to melt. What is the reason for this anomalous behaviour?

A machine was purchased on 1st April, 2015 for Rs. 10,00,000. On 1st October 2015, another machine was purchased for Rs. 6,00,000. Estimated scrap values were Rs. 40,000 and Rs. 20,000 respectively. Depreciation is to be provided 10 % per annum on the machines under the reducing balance system.

(i) Show the machinery account for the year ended 31st March 2016 and 2017.

(ii) Show how the machinery account will appear in the balance sheet as at 31st March, 2017.

Silver articles become black when exposed to air due to formation of:

Which of the following property is shown by covalent compounds?

Which of the following statements is correct in relation to hydrochloric acid and ethanoic acid?

Fill in the blanks in the following statements :

(a) The horizontal rows in a periodic table are called .............

(b) In going across a period (right to left) in the periodic table, the atomic size of the atom .............

(c) On moving from right to left in the second period, the number of valence electrons ..............

(d) When we down in a group in the periodic table, the metallic character of elements ..............

(e) The tendency to gain an electron ................ on moving down in a group of the periodic table.

Ethanol is heated gently in a water bath as shown in the set-up. When potassium permanganate is added in excess, the pink color of potassium permanganate disappears due to the formation of which compound?

Identify the word which the relative pronoun refers to in the sentence.

Copper, which is an element, is mixed with zinc to make brass.

Energy required to break all four C-H bonds in methane is 1662 kJ/mol. Calculate the average bond enthalpy for methane molecule.

Which of the following gets precipitated when dilute hydrochloric reacts with thiosulphate?

Why is froath flotation method only used for sulphide ore? Give reason.

What is the importance of pH?

What type of chemical reaction is this?

NaOH + HCL --------> NaCl + H2O

Give the odour of the gas evolved and name the gas produced when sodium sulphide is added to a solution of HCI in water.

A family uses a light bulb of 100 W, a fan of 100 W and a heater of 3kw, each for 8 hours a day. If the cost of electricity is Rs.2 per unit, what is the expenditure for the family per month of 30 days, on electricity?

Consider the following equation of the chemical reaction of a metal M :

$4M+3O_2$ $⟶$ $2M_2{O}_3$

This equation represents :

(a) combination reaction as well as reduction reaction

(b) decomposition reaction as well as oxidation reaction

(c) oxidation reaction as well as displacement reaction

(d) combination reaction as well as oxidation reaction

is corrosion of metal an exothermic reaction or an endothermic reaction ??