Question

Hey guys please give me the answers quickly I need it so quick I will give you a good rate thank you

The decomposition of an aldehyde solution in carbon tetrachloride is a first order reaction with a rate constant of 1.20 x 10"min". If we start with (aldehyde) = 0.0500 molar, what will the concentration be 150 minutes later? a. 0.00900 M b. 0.0418 M C. 0.00926 M d. 0.00499 M e. 0.000333 M 1 batin tha hafif

Answer 1

Answer:-

Given:-

rate constant (k) = 1.20 $\times$ 10^-3 min^-1

initial concentration of [aldehyde] i.e (a) = 0.0500 M

time (t) = 150 minutes

final concentration of [aldehyde] after 150 minutes i.e (a - x) = ?

As we know that the reaction is first order reaction therefore according to formula

rate constant (k) = 2.303 / time (t) $\times$ log [(a) / (a -x) ]

So

log [(a) / (a -x) ] = rate constant (k) $\times$ time (t) / 2.303

log [(0.0500 M) / (a -x) ] = 1.20 $\times$ 10^-3 min^-1  $\times$ 150 minutes / 2.303

log [(0.0500 M) / (a -x) ] = 180.0 $\times$ 10^-3 / 2.303

log [(0.0500 M) / (a -x) ] = 78.1589 $\times$ 10^-3  

log [(0.0500 M) / (a -x) ] = 0.0781589

On taking antilog of the above value

0.0500 M / (a -x) = 1.19717847577

final concentration of [aldehyde] after 150 minutes i.e (a - x) = 0.0500 M / 1.19717847577

final concentration of [aldehyde] after 150 minutes i.e (a - x) = 0.04176 M

or

final concentration of [aldehyde] after 150 minutes i.e (a - x) = 0.0418 M (i.e the answer)

therefore correct option is 'b' i.e 0.0418 M .