Explore topic-wise InterviewSolutions in .

The correct choice is (a) yes

The BEST explanation: Yes, baking soda as used as a constituent of baking powder which is a mixture of SODIUM Bicarbonate, starch and POTASSIUM bitartrate or cream of tartar rate and in medicine to REMOVE the ACIDITY of the stomach, a mild antiseptic for skin infections and also in the fire extinguisher.

Correct option is (a) nitrogen

To explain: In the presence of the HEAT 2 moles of sodium bicarbonate gives 1 mole of sodium carbonate along with one mole of carbon DIOXIDE and one mole of water in an aqueous MEDIUM. Sodium bicarbonate is alkaline due to anionic hydrolysis.

Correct CHOICE is (c) BAKING soda

The explanation: Sodium Bicarbonate is also KNOWN as baking soda, sodium carbonate is also known as washing soda, Sodium HYDROXIDE is also known as caustic soda and 28% of NaCl solution is known as a BRINE solution.

The correct OPTION is (a) electronics

The explanation: SODIUM carbonate or washing soda, which is represented by the chemical formula Na2CO3.10H2O, is used in water SOFTENING, laundering, CLEANING, paper, Paints and textile industries, it is not used in electronics.

Right ANSWER is (B) anhydrous

To explain: Sodium carbonate crystallizes from water as decahydrate which effloresces. It on exposure to dry air FORMS monohydrate which on heating changes to the anhydrous side that is SODA Ash. Therefore, it is an anhydrous salt.

The correct option is (d) ALKALINE

The explanation: Sodium carbonate on hydrolysis FORMS an alkaline solution, when sodium carbonate reacts with water it forms carbonic acid which is a weak acid and sodium hydroxide which is a STRONG base, therefore FORMING an alkaline solution.

Correct option is (a) Na2CO3.10H2O

For EXPLANATION I would say: Washing soda is nothing but sodium carbonate it contains two atoms of sodium, ONE ATOM of carbon, three atoms of OXYGEN and 10 moles of water in one molecule its chemical formula is given by Na2CO3.10H2O.

Right answer is (a) SOLVAY process

For EXPLANATION I would say: In Solvay process, carbon dioxide GAS is passed through brine solution SATURATED with Ammonia, which results in the formation of SODIUM bicarbonate, which is filtered and dried it is ignited to give sodium carbonate.

Right option is (C) soda LIME

For explanation I would SAY: A mixture of caustic soda and quicklime is known as soda lime, where caustic soda as nothing but sodium hydroxide and quicklime is calcium OXIDE. They are represented by the chemical formula NaOH and CAO respectively.

The correct choice is (d) both FERRIC hydroxide and sodium chloride

Easiest explanation: When 1 MOLE of ferric chloride is reacted with 3 moles of caustic soda, 1 mole of ferric hydroxide which is insoluble and three moles of sodium chloride are FORMED. It is an example of how caustic soda REACTS with SALT.

The CORRECT CHOICE is (B) false

The EXPLANATION is: The atomic radius of Lithium is 1.31Ao while that of magnesium is 1.34Ao, though Lithium and magnesium do not have the same radius, they have a similar radius which is a reason for their diagonal relationship.

The correct answer is (a) magnesium

For explanation I would SAY: Lithium shows diagonal resemblance with magnesium which is an element of group 2 and this resemblance is due to the similar polarising POWER of both these elements. polarizability is proportional to the IONIC CHARGE / the square of the Ionic radius.

Correct option is (c) CARBON dioxide

The best explanation: Lithium carbonate decomposes on heating in order to avoid carbon dioxide whereas other alkali metal CARBONATES do not evolve carbon dioxide, this occurs because lithium carbonate is UNSTABLE in the PRESENCE of heat and is the least stable among the carbonates of alkali metals.

Right answer is (a) YES

For explanation I would say: Yes, Lithium which is unlike the other alkali METALS, REACTS with NITROGEN to form the nitride six MOLES of lithium combine with one mole of a nitrogen atom, in order to form two moles of lithium nitride.

Right answer is (d) lithium

To EXPLAIN: The ELEMENT Lithium whose atomic number is given by 3 is the smallest element in its group that is alkali METALS by size. This is one of the reasons why it has anomalous BEHAVIOR in the PERIODIC table comparatively.

Right choice is (c) Lithium hydroxide and magnesium Hydroxide are weak bases

Easy explanation: The correct statements of the incorrect ones are that; Lithium and magnesium combine with oxygen in order to form monoxides, they are HARD METALS and magnesium chloride is PARTIALLY soluble in water as lithium chloride.

Correct answer is (B) 1

To EXPLAIN I WOULD say: Electronegativity of Lithium is 1.0 and the electronegativity of magnesium as 1.2, they have ALMOST similar electronegativities which is one of the reasons for Lithium and Magnesium’s diagonal RELATIONSHIP.

The correct choice is (b) 0.05 A°

For explanation I would say: The Ionic RADIUS of Lithium CATION is 0.60A°, which is very close to that of magnesium cation that is 0.65A°, therefore the DIFFERENCE between the Ionic radius of cations of Lithium and magnesium is 0.05A°.

Right choice is (b) covalent

To EXPLAIN I would SAY: Both lithium chloride (LiCl) and magnesium chloride (MGCL) are predominantly covalent when COMPARED to other elements in their respective groups, that is alkali METALS and alkaline earth metals.

The correct OPTION is (B) hard

Easy EXPLANATION: Lithium and magnesium are harder than other metals in the group because they have a strong metallic bond among themselves. This is one of the similarities between Lithium and magnesium having a DIAGONAL relation.

Right answer is (a) Rubidium is greater than that of sodium

For explanation: Alkali metals COMBINE readily with halogens to FORM IONIC halides. The reactivity order of alkali metals towards a particular halogen increase in the order; lithium, sodium, potassium, rubidium, and cesium.

Correct answer is (a) True

Easiest explanation: LITHIUM chloride is more covalent than POTASSIUM Chloride, due to the smaller size of lithium BIGGER the onion, larger as its polarizability and the covalent character follow the order of Lithium iodide is greater than Lithium BROMIDE,greater than lithium chloride, greater than Lithium fluoride.

The correct ANSWER is (C) CESIUM oxide is more basic than potassium oxide

For explanation: All the oxides, peroxides and SUPEROXIDES of alkali metals which are formed when heated with OXYGEN are basic in nature. The basic strength of oxides increases in the order of lithium oxide, sodium oxide, potassium oxide, and cesium oxide.

The correct CHOICE is (B) Lithium

For EXPLANATION I would say: All the alkali metals when heated with oxygen form DIFFERENT types of oxides. Lithium forms lithium oxide and some amount of lithium peroxide, while Sodium, Potassium, RUBIDIUM, and cesium can form superoxide.

Correct choice is (c) NaSO4.10H2O

The best I can EXPLAIN: Glauber’s salt contains two ATOMS of SODIUM, one ATOM of sulfur, 4 atoms of oxygen, and 10 moles of water. It is the sulfate of sodium and is represented chemically as NaSO4.10H2O. It is soluble in water.

Correct OPTION is (a) Hydrogen

The explanation: On heating, lithium nitrate decomposes to give nitrous oxide, OXYGEN, and lithium oxide WHEREAS the nitrates of other alkali metals DECOMPOSE on heating and give NITRITES and oxygen. Therefore hydrogen isn’t formed.

Right answer is (B) Sodium NITRATE

The best I can explain: Sodium nitrate (NaNo3) is called Chile saltpeter and POTASSIUM nitrate (KNO3) is called Indian saltpeter. Chile saltpeter which is Sodium nitrate is commonly and naturally FOUND in Chile and Peru.

Correct choice is (d) increases

To explain: The solubility of carbonates and BICARBONATES of alkali metals increases on moving down the group, this is due to the INCREASE in LATTICE enthalpies. The order is as follows in an increasing way of LITHIUM bicarbonate, sodium bicarbonate, POTASSIUM bicarbonate, rubidium bicarbonate, and cesium bicarbonate.

Right option is (B) Sodium carbonate and potassium carbonate

To EXPLAIN: The mixture of sodium carbonate and potassium carbonate together is KNOWN as a fusion mixture. Only Potassium carbonate is as known as PEARL ash. It is sometimes used in quantitative analysis.

Correct choice is (C) insoluble

Easy explanation: All alkali halides except Lithium fluoride are soluble in WATER, this is because Lithium fluoride is soluble in NONPOLAR SOLVENTS as it has a strong covalent bond. Lithium fluoride is REPRESENTED by the formula LiF.

Correct choice is (d) yellow, oxygen

To explain: Sodium Peroxide acquires yellow colour DUE to the presence of superoxide as an impurity. POTASSIUM superoxide is used as a SOURCE of oxygen in submarines, space shuttles and an EMERGENCY breathing apparatus such as oxygen masks.

The correct OPTION is (b) Lithium < Na < K < Rb < Cs

To explain I would say: Two MOLES of ALKALI metal reacts with one mole of hydrogen molecule in ORDER to form 2 moles of alkali metal hydride. The correct order of reactivity of alkali metals towards hydrogen is LI < Na < K < Rb < Cs.

The CORRECT OPTION is (b) formation of oxides

Explanation: On exposure to moist air, the surface GETS tarnished due to the formation of oxides, HYDROXIDE and carbonates. Few examples are sodium hydroxide, sodium CARBONATE, potassium hydroxide etc.

The correct choice is (a) true

For explanation: Due to the presence of loosely held Valence Electrons which are free to MOVE throughout the metal structure, the alkali metals are good conductors of HEAT and electricity. Electrical conductivity increases from top to bottom in the order, so CAESIUM has the HIGHEST electrical conductivity in its GROUP.

The CORRECT option is (b) reducing

Explanation: All the alkali metals are good reducing agents due to their low ionization energies. The reducing character of group 1 elements follows the increasing ORDER of Sodium, Potassium, rubidium, CAESIUM and lithium.

Correct OPTION is (d) blue

The explanation: Alkali metals and their salt impart characteristic colours to the flame because the OUTER electrons get excited to higher energy levels. When the electrons RETURN to the original STATE, it releases VISIBLE light of a characteristic wavelength which provides colour to the flame. The colour of the Flame of the caesium is blue.

Right OPTION is (c) decrease

For EXPLANATION: The alkali metal atom SHOW only +1 Oxidation State, because of their unipositive Ion at the time the stable noble gas configuration. The atomic volume of alkali metals is the highest in its period and goes on INCREASING down the group from top to bottom.

Correct answer is (a) Yes

Explanation: The degree of hydration depends UPON the size of the cation, smaller the size of the cation, greater is its hydration ENTHALPY. The relative degree of hydration in an increasing ORDER is Li^+ > Na^+ > K^+ > RB^+ > Cs^+.

Right option is (b) electropositive

To EXPLAIN I would SAY: Due to LOW ionization enthalpies, alkali METALS are strongly electropositive or metallic in NATURE and electropositive nature increases from Lithium to caesium due to decrease in ionization enthalpy.

The correct answer is (a) Yes

The best I can explain: The first IONIZATION enthalpy of alkali METALS is the lowest among the elements in their respective periods and increases on moving down the Group. The SECOND ionization enthalpies of the alkali metals are very high because by RELEASING an electron, ions REQUIRE noble gas configuration, so removal of the second electron is difficult.

The correct option is (b) low

To explain I would say: The melting and boiling POINTS of alkali metals are quite low and they decrease down the group due to WEAKENING of their metallic bonds. Francium is the only ELEMENT in this group which is a LIQUID at ROOM temperature.

Correct choice is (a) TRUE

Easy explanation: The alkali metals have the biggest ATOMIC radii in their respective PERIODS, atomic radii increases as we GO down the group due to the ADDITION of a new shell in each subsequent step. So the above statement is true.