Which of the following statement(s) is(are) correct?
`CaH_(2)` hydrolith is used for production of `H_(2)`.
`BeO` is covalent due to small size but has high melting point
`CaCl_(2)` is widely used for melting ice on roads because `30%` eutectic mixture of `CaCl_(2)` ice freezes at `218K`
Carbides of Beryllium react with water liberating methane gas

Which of the following statement is correct when a mixture of CaCl_(2) and K_(2)Cr_(2)O_(7) is gently warmed with conc . H_(2)SO_(4) acid ?

Which of the following statements are correct for SO_(2) gas? (a) It acts as bleaching agent in moist conditions. (b) Its molecule has linear geometry. (c ) Its dilute solution is used as disinfectant. (d) It can be prepared by the reaction of dilute H_(2)SO_(4) with metal sulphide.

Carboxylic acid, although unreactive to alcohols, reacts in the presence of small amount of conc. H_2 SO_4 or with 2-3 % of HCl ? RCOOH + R'OH overset (H^(oplus)) hArr RCOOR' + H_2 O Which of the following statements is//are correct about the above reaction ? (I) This reaction is called Fischer esterification reaction. (II) The equilibrium is shifted to R.H.S if H_2 O is removed by azeotropic distillation with benzene. (III) The reaction of RCOCl and R'OH to give ester (RCOOR') is irreversible and more feasible than esterification of RCOOH . (IV) If the above esterification of RCOOH is carried out in excess of R'OH , the equilibrium is shifted to R.H.S .

Which of the following statements are correct? (a) S___S bond is present in H_(2)S_(2)O_(6) (b) In peroxosulphuric acid (H_(2)SO_(5)) sulphur is in + 6 oxidation steta (c ) Iron powder along with Al_(2)O_(3) and K_(2)O is used as a catalyst in the preparation of NH_(3) by Haber's process (d) Change in enthalpy is positive for the preparation of SO_(3) by catalytic oxidation of SO_(2)

How many of the following statements are correct for green vitriol? 1. it can be used for the preparation of Mohr's salt. 2. It is a hydrated salt and its anhydrous form is white in colour. 3. The decomposition reaction of its anhydrous form is redox in nature. 4. It is used for making fenton's reagent used as a catalyst in organic chemistry. 5. It can be used for the preparation of Potassium ferrocynide. 6. It has same number of molcules of water of crystallization as white vitriol or blue vitriol 7. It turns brownish-yellow on exposure to atmosphere. 8. Its aqueous solution is acidic in natrue due to hydrolysis. 9. Out of the decomposition products of its anhydrous form, only one can turn acidified K_(2)Cr_(2)O_(7) solution green.

How many of the following statement/s is/are correct? (1). For isothermal process DeltaE and DeltaH are 0. (2). On increasing temperature pK_(w) of water decreases. (3). For adiabatic process DeltaS is always 0. (4). Indicator methyl orange can be used for titration between strong acid and weak base. (5). At triple point liquid. vapour and solid state are in simultaneous equilibrium with one another. (6). DeltaH_(f)^(@) of D_(2) (gas) is zero. (7). Molal elevation constant (K_(b)) depends upon nature of solute. (8). Be does not give flame test. (9). Solubility of AgCN increases in KCN solution.

Lithium only forms monoxide when heated in oxygen. Sodium forms monoxide and peroxide in excess of oxygen. Other alkali metals form superoxide metals superoxide with oxygen i.e., MO_(2) . The abnormal behaviour of lithium is due to small size. The larger size of higher metals also decides the role in formation of superoxide. All the three anions abstract proton from water. The three anions are raleted to each other as follows: underset("oxide ion")(O_(2)^(2-)overset((1)/(2)O_(2))(to)underset("peroxide ion")(O_(2)^(2-))overset(O_(2))(to)underset("superoxide ion")(2O_(2)^(-)) Q. Which compounds will liberate oxygen when reacts with ice cold water?

Which of the following is (are) correct statements? i. 0.1 M CaCl_(2) has higher boiling point than 0.1 M NaCl . ii. 0.05 M Al_(2)(SO_(4))_(3) has higher freezing point than 0.1 M K_(3)[Fe(CN)_(6)] . iii. 0.1 M glucose exerts higher osmotic pressure than 0.08 M CH_(3)COOH (25% dissociated). iv. Vapour pressure of 0.05 M urea solution is greater than that of 0.05 M KCl solution. a.i,ii ,b.ii,iv , c. i,ii,iii , d. i,ii,iv

Of the following statements , which are true for S_(N)2 reaction. (a) Tertiar alkyl halides reacts faster than secondary. (b) The absolute configuration of product is opposite to that of the reactant when an optically active substrate is used. (c) The used shows first order kinetics. (d) The rate of the reaction depends markedly on the nucleophilicity of the attacking reagent. (e) The mechanism is one step. (f) Carbocations are intermediate. (g) Rate prop [Alkyl][halides] (h) The rate of the reaction depends on the nature of the leaving group.

Go through the following statements (i) The most widely used compound as source of ethylene is ethephon. (ii) Ethylene helps the plants to increa their absorption surface by promotin root growth and root hair formation. (iii) 2, 4 - D is mainly used to kill mature monocotyledonous plants. (iv) Spraying juvenile conifers with GAs has- tens the maturity period, thus leading to early seed production. Which of these are correct