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GMLB/PRE BOARD EXAMINATION 2023-24 CLASS :X FULLMARKS: 80 TIME : 2 HOURS SUBJECT :CHEMISTRY You will not be allowed to write during the first 15 minutes. This time is to be spent for reading the question paper. The time given at the head of the Paper is allowed for writing the answers. Section A is compulsory. Attempt any four questions from Section B. The intended marks for questions or parts of questions are given in brackets [ ]. [ SECTION A (Attempt all questions from this section) t QUESTION 1: Choose one correct answer to the questions from the given options: [15] (i) The alloy which can be used for making body of aircraft is (a) Stainless steel (b) Solder '(c) Duralumin (d) Bronze (ii) A concentrated acid was added to hydrated copper sulphate, and it \ changes its colour to white. The acid taken was (b) Nitric acid {a) Sulphuric acid (c) Ethanoic acid (d) Hydrochloric acid Page 11 ( ., (iii) Ammonium hydroxide was added to a solution of the salt and a dirty green precipitate was formed which was insoluble in the excess c the reagent The salt taken is (b) Zinc chloride (a) Copper chloride (d) Ferric chloride Ferrous chloride (iv) The drying agent which is used for hydrogen chloride gas is Cone sulphuric acid (a) Calcium oxide t (d) Silica Gel (c) Phosphorus pentoxide (v) When an aqueous solution of copper sulphate was electrolysed, the - colour of the electrolyte faded. Which of the following can be theelectrod es P. anode: platinum cathode: platinum Q. anode : copper cathode : copper anode : copper cathode : platinum (a) Only P (b) Only Q (c) Both P and Q (d) Both Q and R (vi) Which of the following compou nd is an alkyne? (a) CJfu (b) CsH12 (c)CsH10 ~CJi io (vii) The compound which reduces black copper oxide to red copper is (b) Sulphuric acid (a) Nitric acid (c) Ammonia (d) Hydrochloric acid Paee NOs )) 0 , hz_sJ"' "' ~l'" - " .J.. LU 0 -c..u o ,. '-- ,_.-C (viii) The catalyst used for Contact Process is (b) Finely divided iron (a) Vanadium pentoxide (c) Manganese dioxide (d) Phosphorus pentoxide (ix) The periodic property which increases down a group (b) Ionisation potential (a) Electron affinity _(_d_) Metallic character (c) Electronegativity - (x) Which characteristic is TRUE for ionic compounds. P. They have low boiling points. =::z:Q., They dissolve in water. -R........They are mostly solids. (a) Only P (b) Only Q (c) Only R (d) Both Q and R (xi) Which one is a dibasic acid? (a) Acetic acid (c) Nitric acid 'cb),Hydrochloric acid ( d) Carbonic acid (xii) An element is having a valency 1, has a low ionization energy, and is a strong reducing agent. Which statement is correct about the element? P. It is placed in group 1 of the periodic table. Q. It is capable of forming a cation (a) Only p _ (b) Both P and Q (c) Only Q (d) Neither P nor Q Page I 3 ,~~' ,-~,~,~~ ~~'"'~' ~~~,,~f''~S~\'~~~~1\t~~~\\-~~,~--\\'\\'\~, ~~,'\~" ,~,x~~ ").~,,~ ,1'~"~,'"\\~ ,~ ,l\' '~\~It""~ ,, , ..... ~- '"~ "'"'\~,~ ~~"'~~\lt '-,~~\~ ~"'' ~~~-#J.\~ \ ,~\,\t}~ \~\ ~XQ ft,~ , -.:l.\ ,~~) ~, ~"C ,~\ ,~\ \ ~ ~ , , ~ ,.1'~~,,~ ~'\,,~ ,~) ,~~~tc'" \'~ \~)~ -~ \' \~) ,~~). ,,,, ..,,~~ ~' ,\ ,,,,~,~ ,'('" \~,,~ "~" ,~\\\~ .. ',~,,~~.... ,~;- ' " ~-1''\!. ,, (xiii ) The ore whic h can be purified by Bay er's pro c~ is (b) Zinc blende (a) Red haematite -(cl Bauxite (d) Alumina (xiv) The nmnber of moles in 8 g of oxygen is (a)0 .25 (b) 1 (c) 0.5 ) (d) 0 .75 (xv) In the reaction of esterification, if ethyl acetate is prepared, then tb acid and alcohol whi ch has undergone reaction is \ '00 Methanoic acid and ethanol (b) Etbanoic acid and methanol {l')- Etba ooic acid and ethanol (d) Metbanoic acid and methanol QU EST ION 2: (i) The diagram below represents the process of electrop lating of iron bar with nickel. [5] -n;a -n,u.;; - .. -:-.: . 'UMi """"" \J, So4 (a) State the electrolyte which you think should be use d (b) Why is the iron bar to be electroplated placed at the cathode? Of what material do you think the anode should be mad e ofl (c) Can you use alternating current for the process? Just ify your answer. heel ' (ii) Match the following Column A with Column B: [SJ Column B Column A (a) Acetic acid (b) Sulphuric acid (c) Methane ( d) Magnesium chloride c_ (i) Covalent compound ~- (ii) Froth floatation (iii) Contact process ' (iv) Vinegar (e) Zinc blende d (v) Electro valent compound (m) Complete the following by choosing the correct answers from the [5] brackets: (a) Ethane will undergo _ _ reaction..(addition/substitution) (b) 1 mole of carbon dioxide will occupy _ _ litres at STP.(22.4/44.8) (c) In the fountain experiment , if the colour of the fountain is b\u~ then the gas taken in the flask is ___.(ammonia/hydrogen chloride) - ---- (d) If an element is a me~ then its position in the periodic table is _ _ _( 2Jl7) probably in group (e) If an element takes 2 electrons and foimS an ion A2-, then the numbeT of electrons in its outermost shell was_ _(2/6) - (iv) Identify the following- l 51 (a) The self-linking property of carbon.C-\ '- ,,, , \\ '1"(b) A type of salt formed by the complete replacement of the ionisable hydrogen atoms of an acid. f' c.. , c_ o- '!(c) Process of heating a concentrated ore in absence of air. l"n_\,-. "...__...._,' r-17\' '-J' - \ V' 1~ ' / (d) The bond formed between two atoms by sharing a pair of electrons provided entirely by one of the combining atoms. C>" (e) A group of organic compounds which can be represented by a general formula in which the successive compounds differ by a -CH2 group. (v) (a) Draw the structural diagram for the following compounds- [5] 1. Propan-2-ol 2. 2,2-dimethyl propane 3. 2-chloro pentane (b) Give the IUPAC name of the following compounds- 1. H I 'H 0 \ I H-C-C-C-14 I u I 2. H ._ H I H-c- t= I A .c~~_,- I h H ' SECT IONB (Attempt any four questions) QUESTION 3: (i) Draw the electron dot diagram of hydro nium ion. -~. [2] (ii) A compo und of A and B has the empir ical fonnu \a AB2.. Its empir ical formu la weigh t is doubl e its vapou r densit y. Deter mine its l21 molec ular formu la. (iii) A and B are two elements which are having an electronic configuration of 2,8,2 and 2,7 respectively. Using this information [3] complete the following- (a) _ _ _ is having lower ioniz.ation potential. - (b) ___ forms an anion. (c) _ _ _ is a reducing agent. (iv) With respect to laboratory preparation of nitric acid, answer fue l31 following(a) Why is an all glass apparatus used'? (b) The acid obtained in the laboratory is slightly )'ello w. Wh':J'? (c) Give the equation for the reaction. QUESTION 4: (i)Identify the reactant Q and write balanced equation for the following: [21 Diute sulphuric acid reacts with a salt Q to give sodium suphate and a gas with smell of rotten eggs. Pip 17 (i i) W it h re fe re e to th e ex tr ac ti on o m et h o d , an sw ernc f A lu m in i th e fo ll ow in gum by electrolYtic (a ) N am e th e o th er co m po un d o fa l (b ) 'Wh um 1n 1u m ad de d to al . y is po w de re d el ec tr o ly ti c m ix tu re ? co ke sprinkled over the surfac e ununa f O th e [2] (i ii ) G iv e b al an ce d eq ua ti on for ea ch o f the fo llowing[3 ] ( a) L ab o ra to ry pr ep ar at io n o f methane from sodium ethanoate. (b ) O x id at io n o f ca rb o n w it h cone. nitric acid . ( c) A ct io n o f d il u te hy drochloric acid o n silv er nitrate solution. (i v ) R aj es h p re p ar ed th re e co lo ur le ss soluti ons A , B an d C having pH o f 7 , 11 an d 2 . Id en ti fy th e so lu ti on w hi ch w il l (31 (a ) T u m re d litmus p ap er b lu e. (b ) P ro d u ce ca rb o n d io x id e w h en tr ea te d wit h sodium carbonate. ( c ) W il l sh o w n o co lo u r change with re d o r bl ue litmus paper j Q U E S T IO N S : (i ) Name the gases ev olved, when c o (a ) C al ci u m carbid e reacts with water. . ; (b ) A m m o n ia reac ts w it h excess o f cblonn e. (i i) The at o m ic numb [2] d t . 15 State th e group an d p en o is [2] er o f a n elemen to which the element bel ongs. Pa& , [3] "d" salt nnal and an ac1 ic f . (a) Sulphuric acid can ionn a no ward displa ceme nt o arr. d . . (b) Ammonia gas is collectedbY own e condu cts e\ectn city (iii) Give reasons : r. blorid . . . . ( c) An aqueo us soluti on of sod ium c is given by acid nitric hos horus and Of P 2 P g 6. en ) The reacti on. betwe (IV the follow ing equati on- p + sHN03 - . H:J>04 +5 NCh + H20 [P=3 l, H=l,N =14,0 =16] [31 Calculate(a) The mass of nitric acid used. (b) The mass of phosphoric acid formed. (c) The volume of nitrogen dioxide evolved at STP. " O~ QUE STI (i) 67 .2 litres of nitt9g en monoxide bums in 44.8 litres of oxygen to form nitrogen dioxid'e'according to the equation 2NO +oz-+ 2N "" Calculate the volume of unuse d ~en and nitrog en dioxi de forme d. l21 (ii) Give one chemical test to distinguish betwe en the follo win~ ' "-compounds(a) Hydrochloric acid and sulph uric acid (usin g 'Qarium chlor ide "'-solution) (b) Calcium nitrate and zinc nitrate (using amm onium hydroxide [2] solution) ' 1 Pase I 9 (ili ) Na me the fol low ing - (a) An ele me nt wh ich has the hig hes t ionization potential. (b) An alkali metal in period 3. [3] (c) An element which has the highest ele ctron affinity among the halogens. (iv) A compound contains 47.8 % of Zin c and 52.2 % of chlorine. Find its empirical formula. [Zn=65, CI 35.5] [3] "QUESTION 7: State the composition of the following allo ys [percentage not required][2] (a) Solder (b) Brass (ii) State on e relevant observation for the following[2] (a) Am mo niu m hydroxide solution is add ed to ferric chloride sol uti on . (i) (b) Eth ene is passed through bromine wa ter. (iii) Wi th reference to the electrolysis of molten lead bromide, answer the following(@ )ta te yo ur observation at the cathod (b) Th e reaction at the cathode. e and anode. [3] (iv) Select the method used for preparati on of the following salts from the lis t giv en below (a) Sodium chloride (b) Le ad chloride (c) Iro n (III) chloride [3] Pa1e I 10 le sation C. Doub li a tr u e N . B t n e displacem .. List: A. Simple ct synthesis A e ir D . D n o ti si o decomp : QUESTIONS _:ro Calculate th \ ''\ ia . 4 g of ammon 3 in s le u c le o er o f m e numb [N = 1 4 ,H = l] [2] hrases. [Only /p s rd o w g in d d a g statements by in w o ll ntence is not fo se e f th o t e c g e n rr a o h C C . ~ d e ( phrases is allow s/ rd o w f o n io it add d r is hydrogen an te a allowed.] w f o s si ly o formed b y electr ts c u d ro p e ::> 61 c i J j ~ h T (a) uce hydrogen d ro p oxygen. to id c a c ri [2] acts with sulphu re e d ri lo h c m iu d o S ) (b borato.ry and la e th chloride gas. in s a g e d ri d hydrogen chlo re a p re ric acid. For the p lo k h a c n ro u d a y h e c u (iii) R d e in water to pro m a s e th d e lv o s dis cial arrangement. e sp a d e s u e h e gas, he used for the t n e m dissoluti' o' n o f th e g n a rr a l ia g e s t, what spec g u s u o y im c ) (a [3] t. n e dissolution? m e g n a rr a e vantages o f th [3] (b) State two ad se c n a following subst e th fy ti n e Id ) v (i en house gas. re g a is h ic h w e ~ss, o_dourless rl u lo o c a s e (a ) A n alkan c u d e salt, which pro th in t n e s lt with dilute re sa p e n th f o n o ti c (b) A n io a ater milky, on re w e m li s . . rn tu h g a s w h ic an ice like s rm fo ' d ie . if d id li c sulphuric a d which when so n u o p m o c ic n a ( c ) T h e org mass. Pa&e I 111
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