State whether the following sentences are true or false: (a) Metals in the second group are called alkali metals. (b) Alkali metals are not found in free state in nature. (c) Baking soda is chemically sodium hydrogen carbonate. (d) Portland cement is basically silicates and alu minates of calcium.

State whether the following sentences are true or false: Baking soda is chemically sodium hydrogen carbonate

State whether the following sentences are true or false: Portland cement is basically silicates and aluminates of calcium

The group 1 metals of the periodic table of elements are collectively called alkali metals. Alkali metals are never found free in nature. Give reason.

State whether the following statements are true or false. a. In benzene, carbon uses all the three p obitals for hybridisation. b. Ácetylene is a tetrahedral molecule. c. Branched chain alkanes, alkenes and aromatic hydrocarbons have high octane numbers. d. Ethyne can be distinguished from ethene by using cold dilute KMnO_4^- e. In cracking, the larger molecule are broken down into smaller molecules and in reforming, cyclic and acyclic alkanes are converted into arenes.

The order of reactivity of some metais are given. Answer the following questions by analysing it. Al gt Zn gt Cu gt Au a) Which metal is produced by the electrolysis of its molen salt? b) Matal occur in free state in nature. c) Metal produced by the self oxidation-reduction reaction. d) Metal are which is reduced by carbon.

Which of the following statements are true? i) Elements which are least reactive occur in free state or native state ii) Earthly or undesired materials present along with ore are called gangue iii) Among metals, aluminium is the most abundant in the earth crust iv) All ores are minerals but all minerals are not ores v) Gemstone "Ruby" is the impure form of Al_2O_3 containing impurity : Co vi) The set of d-block elements Cu, Ag, Au mostly occur as sulphide ore

Choose the false statements and rewrite them. (a)Alkali metals possess both +1 & +2 oxidation states. (b) Lithium is found to be the strongest reducing agents among the alkali metals.(c) Manufacturing of rayon is known as viscose process. (d) Washing soda is used to remove temporary hardness of water.

Which of the following is/are wrong statements? a) Alkali metals, alkaline earth metals and helium are s-block elements. b) Pnicogens and halogens are p-block elements. c) The first member of the lanthanide series is lanthanum. d) The lightest liquid metal is gallium. e) Group 17 contains no metals. f) Elements whose atoms have two outermost shells incomplete are called transition elements

The correct match among the following is (a) Lithium, Sodium, Potassium (i) Alkaline earth metals (b) Beryllium, Magnesium, Calcium (ii) Semi-metals (c) Oxygen, Sulphur, Selenium (iii) Alkali metals (d) Silicon, Germanium, Arsenic (iv) Chalcogens