What current is to be passed for `0.25` sec for deposition of certain weight of metal which is equal to its electrochemical equivalent ?

Correct Answer - B Equivalents of metal=Equivalents of metal sulphate `("wt.of metal")/("Eq. wt. of metal")("wt. of metal sulphate")/("Eq. wt. metal sulphate")` `(2)/(x)=(6.8)/(x +48)` `6.8x=2x+96` `4.8x=96` `x=(96)/(4.8)=20`

Correct Answer - D Charge on 1 mole electron `= N xx e = Q` = Faraday .

Correct Answer - A `w = Z xx i.t` if `ixx t = 1 ` coulomb , when w = Z .

Correct Answer - B `W = Z xx C xx t = 0.00118 xx 0.5 xx 200 = 0.1118` g

Correct Answer - A `W = ( I xx t(s) xx E)/(F)` `therefore E = (W xx F)/(I xx t) = (0.108 xx 96500)/(0.5 xx 193) = 108`

Correct Answer - A At mass of element `= 20xx3=60` Formula of its oxide is `M_(2)O_(3)` `:.` Molecular mass of its oxide `= 2xx60+16xx3` `= 120 + 48 = 168`

Correct Answer - D 1000 mL 0.1 NHCl = 0.1 g eq of metal carbonate `=2gxx10=20g` 1 g eq of HCl is neutralized by 1 g eq. of metal carbonate `=(20)/(0.1)=200`

Correct Answer - B Atomic mass of metal = Eq. mass `xx` valency `=20xx2=40` Molecular formula of anhydrous chloride `=MCl_(2)` Molecular mass of chloride `=40+2+xx35.5 =111`

Correct option is: A)\(sec^4\theta - sec^2\theta\) \(tan^2 \theta + tan^4 \theta\) = \(tan^2\theta (1+ tan^2\theta) \) = \(tan^2\theta.sec^2\theta \) (\(\because\) 1 + \(tan^2\theta= sec^2 \theta\)) = \((sec^2\theta-1) sec ^2\theta \) (\(\because\) \(tan^2\theta= sec^2 \theta\)-1) = \(sec^4\theta - sec^2\theta\)